Home/BlogThe standard explanation of the “greenhouse effect” is that it keeps the surface of the Earth warmer than it would otherwise be, through infrared radiation downwelling from the atmosphere. Even though this IR radiation is being emitted at a lower temperature than the surface, it actually keeps the surface warmer. Some people have trouble with this explanation, claiming it violates one or more laws of thermodynamics.
As I have discussed ad nauseum, the temperature of a heated object is always determined by rates of energy gain and energy loss, and that energy loss is almost always a function of the object’s cooler surroundings.
Whether one views the greenhouse effect as extra infrared energy gained by the surface from the cooler atmosphere, or just a reduced rate of infrared energy loss by the surface to the atmosphere and outer space, the effect is the same: a surface temperature increase.
I’ve been toying with a few different ways to demonstrate this effect with a simple experimental setup using household items. Apparently the IR thermal imager, which I showed directly measures the surface temperature effects of varying levels of downwelling IR sky radiation on a microbolometer within the instrument, is not sufficient for some people.
So, I’ve come up with the following simple setup, and if I carry it out, I want predictions from readers here of what will happen to the temperatures of the 2 heated metal plates:
The two metal plates will be heated in the oven to the same temperature, then placed vertically next to each other, but separated by a sheet of Styrofoam. Obviously, the plates will cool, partly by conduction to the surrounding air. The above cartoon is just a rough approximation of the setup. I will probably have the ends of the heated plates covered by Styrofoam as well, to help reduce conductive heat loss.
But the plates also cool from infrared energy loss. So, I will expose one of the heated plates to a third plate that I will have chilled to at least 0 deg. F in the deep freeze.
Finally, I will expose the other heated plate to a 4th plate just at the ambient air temperature, say 80 deg. F.
Very thin sheets of polypropylene (Saran wrap), which are nearly transparent to IR radiation, will be used to minimize the movement of air currents between the heated plates and their cooler counterparts. All 4 plates will be coated with high emissivity (0.99) Krylon flat white #1502 paint.
My question is this: Will the two hot plates cool at different rates? I predict the heated plate exposed to the ambient (80 deg. F) plate will consistently stay warmer than the other heated plate exposed to the chilled (0 deg. F) plate.
Of course, if one waits long enough, all plates will come to the same temperature, since the hot plates are not actively heated (like the climate system is by the Sun) and the cold plate is not actively chilled (which would partly mimic the infrared energy sink of deep space).
The main point is that cooler objects which surround heated objects affect the heated objects temperature. As far as I can tell, this is a universal truth, with examples all around you. I find it mind boggling that some people do not accept it. (For anyone tempted to say, “But a cooler star doesn’t make a hotter star hotter still”, stay tuned for an experiment Anthony Watts has been working on).
I will monitor the plates’ temperatures with my FLIR i7 thermal imager. Because there is still a small amount of reflection from the heated plates (0.01) the thermal imager must be pointed at an angle which will not pick up reflection from the cooler plates, which would bias the results. Another option would be to buy 2 inexpensive car thermometers with a remote display.
Again, I want to hear some predictions: Will the hot plates cool at different rates? If so, do you see a mechanism other than infrared energy transfer which will explain the different rates of cooling?
If you see pitfalls in the experimental setup, then feel free to point them out and suggest how to mitigate them.
UPDATE: I will be periodically checking in and deleting comments which do not directly address the above experiment and what results it will produce…unfortunately, the comments are already getting sidetracked.
Roy,
It’s probably overkill, but you might repeat the experiment under various permutations — swapping the hot plates left/right; swapping the cold/ambient plates left/right; swapping which plate is cold and which is ambient, etc. This would tend to cancel out any biases that might be introduced by plates being different mass, or air currents in the room, or slight asymmetries in the positioning, etc. It is just one way to head off potential objections before they can arise.
You could even get ‘fancy’ and use a “Fractional Factorial Design” to choose a subset of all the possible permutations and to analyze the results. 🙂
http://en.wikipedia.org/wiki/Fractional_factorial_design
(I’d be willing to help with that.)
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And of course, I expect the object exposed to the “cold plate” to cool more rapidly than the object exposed to the “ambient plate”.
Yes, all of that would help. Just a lot of trouble, obviously.
May 16th, 2013 by Roy W. Spencer, Ph. D.: “The standard explanation of the “greenhouse effect” is that it keeps the surface of the Earth warmer than it would otherwise be, through infrared radiation downwelling from the atmosphere. Even though this IR radiation is being emitted at a lower temperature than the surface, it actually keeps the surface warmer. Some people have trouble with this explanation, claiming it violates one or more laws of thermodynamics.
As I have discussed ad nauseum, the temperature of a heated object is always determined by rates of energy gain and energy loss, and that energy loss is almost always a function of the object’s cooler surroundings.”
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Right, but you are confusing 2 things with regard to temperature: energy gain from warmer objects and energy gain from cooler objects. Please, focus on this point: energy gain from cooler objects is impossible under normal conditions.
You really need to focus on that. Again, both increase and decrease in temperature are possible, warmer objects can cause increase in temperature of colder objects, but not the other way round: colder objects can not cause increase in temperature of warmer objects. This includes also slowing down cooling, which is a warming effect too, we can call it relative warming.
This is very easy to prove. The assumption that a colder object can have a warming effect on a warmer object leads in case of a warmer object being initially at a stable temperature to an endless mutual warming of both objects without any additional input of energy, that is warm warms cold, cold warms warm back and so on endlessly, which is absurd and physically impossible.
In all cases about insulation or “colder surroundings keeping warmer” it is about preventing cooling by something cold. Right, cold cools warm by conduction and convection, that is all, and if we keep cold away from warm, warm will stay warm or cool less, everyone knows that. None of these examples proves any warming effect of cold on warm. You only need to look closely at what is really going on in these examples.
Don’t you have a blanket on when you sleep? Why? It’s colder than you.
Scott Scarborough says “Don’t you have a blanket on when you sleep? Why? It’s colder than you.”
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No, under typical conditions a blanket keeps the colder air from cooling your body. Second, it is YOU that warms the blanket and the air between the blanket, not the other way round. As a result you have the warmer blanket warmed by you and the warmer air warmed by you as well around your body, instead of the colder air. So, it is not the cold blanket, it is the warm blanket that keeps you warm. When a cold blanket touches you body, you feel COLD, it COOLS you.
Cold cools, warm warms, in short. “Cold warms” is nonsense, absurd and physically impossible, see the explanation in my comment above.
Roy says: “Again, I want to hear some predictions: Will the hot plates cool at different rates? If so, do you see a mechanism other than infrared energy transfer which will explain the different rates of cooling?”
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Roy, of course they will. It is to be expected, because they are in different conditions.
The air will move around the plates differently, the air temperature close to the plate will be different, therefore the plates will cool differently.
So, before you can explain anything with “cold has warming effect on warm” (this includes slowing down cooling), you need to account for differences in the air movements and the air temperatures around the plates. I doubt you can and are going to do that. Without that you can not prove your thesis. It will end in another misleading demonstration, that is all, even if misleading is not your intention.
Another thing is this constant confusion about warming versus slowing down cooling. Do you agree at least, that if your assumption about back radiation from colder bodies slowing down cooling of warmer bodies requires a literal warming in absolute numbers, if the warmer body is not in the process of cooling at all, but initially at a stable temperature?
Great idea for an example and experiment!
Ideas and experiments are generally good, but until now I have only seen “thought experiments” proving “back radiation warming” or fakes. Here is an example of the latter kind (http://wattsupwiththat.com/2013/05/28/slaying-the-slayers-with-watts-part-2/) and a deleted comment explaining why it is fake: “Compared to the experiment presented yesterday, the results contradict each other. Both can not be true, so at least one report is not correct. I think that the one presented yesterday by Anthony was genuine. Hence the one presented above is not. I do not buy it, sorry. Another point is that the Anthony’s one has not proven what it was intended to prove, but let us put it aside.
In the Anthony’s experiment the convection cooling of the bulb was reduced by the mirror and it caused (let us say for the debate’s sake, together with the back radiation from the mirror) 10C increase in temperature. In the report presented above much more reduced convection (enclosure!) and much more back radiation from the glass (that is very much opaque to IR) allegedly caused the same 10C increase in temperature. This can not be true. Therefore the central comparison to the effect of the foil can not be true either.
So, Anthony made a mistake by misinterpreting the opponent’s point and the “greenhouse effect” as presented by the IPCC and as a result conducted an experiment that was unrelated to the actual point. This is something I can understand. The thing presented above seems to be of quite a different nature to me. But OK, maybe the thermometer was broken, no problem.”
I agree with your prediction, Dr. Spencer. All anyone has to do is note the very slow cooling rate during cloudy nights.
(snip) please stick to the subject of the post, Phillipe.
Roy, I am stunned by the “experiment” you plan to do: Everybody understands that the outside temperature affects the inside temperature of a house under constant inside heating.
But it is an abuse of both physics and language to claim that a cold exterior is heating a warm inside, when the true physics is that the a warm inside is heating a cold exterior, that is that there is a uni-directional flow of heat energy from a warm inside to a cold outside, by conduction or radiation.
I cannot understand from where you get such a strong urge to twist physics and language by claiming that a cold outside is heating a warm inside by “back conduction” or “back radiation” through the space separating inside from outside. Why do you insist propagating false physics which violates the 2nd law?
Claes, you are the one abusing physics, and twisting my words. I never claimed that “a cold exterior is heating a warm inside”, only that it affects the temperature of the warm inside. Also, I never claimed there was such a thing as “back conduction”.
I *do* however claim that the atmosphere emits IR radiation in all directions, and if the atmosphere emits IR downward it must then affect the surface temperature.
Since you insist on twisting what I say, consider yourself banned along with the other Slayers I have banned.
Claes,
Roy Spencer said:
“The main point is that cooler objects which surround heated objects affect the heated objects temperature.”
How you twist this to:
“But it is an abuse of both physics and language to claim that a cold exterior is heating a warm inside..”
stays your secret. I guess.
I am surprised that you seem not to understand steady states and can’t solve the system of differential equations that govern the thought experiment that Roy Spencer suggests even using two bodies. One with a heat supply with the boundary condition dq/dt = 0 and an unheated body placed next to the first body in vacuum.
use Mathematica or Matlab and program it yourself.
Best regards
Günter
Claes makes the mistake of muddling the meaning of the word heat. It has two main relevant meanings: one is to change the temperature of something, the other is to pass energy to a closed system by means other than the application of work. The ‘change temperature’ meaning is an ordinary language usage, but is not admitted in strictly physical usage. The ‘pass energy to a closed system’ meaning is the physical usage. In ordinary language, the Joule experiment with the rotating paddle “heated” water. In physical terminology, the water’s temperature was increased by the passage of energy as work, not heat, from the surroundings to the water. This kind of work is called isochoric work, because it acts without changing the volume of the receiving body. It is also called ‘shaft work’ because the paddle is driven from the outside by a rotating shaft, that does not change the volume of the water. The shaft work imparts kinetic energy to the water, which is then dissipated into the internal energy of the water, thus raising its temperature, but not by passage of energy as heat from a heat reservoir in the surroundings. Claes and his followers, amongst other mistakes, muddle the two meanings.
Houses have insulation in the walls. Even thought that insulation is always colder than the house (in the winter) it still does a great job of keeping the house warmer than it would otherwise be.
Claes:
I would suggest that it is a violation of your interpretation of the second law of thermodynamics.
We obviously went to different schools as I live in Oz but I was taught it referred to net energy flow.
HotR – CoolR = NetR
I have no doubt that this is what Dr Spencer’s excellent experiment will demonstrate. If I’m wrong I’ll have to change my position, but I doubt id I’ll have to.
Hope you are just as prepared to change yours.
(snip) Bryan, if you have a specific example of an ambiguous phrase from the above post regarding warming or cooling, please note it and I will clarify.
Cool objects can obviously slow the cooling of warmer objects if there is an even cooler region beyond the cooler object.
However, that is not a good analogy for an atmosphere or the greenhouse effect.
For an atmosphere around a planet external energy from the sun flows straight through at equilibrium and there is additionally a balanced and entirely separate energy exchange between surface and atmosphere.
The energy exchange between surface and atmosphere is effected by non radiative processes and the radiative energy content of the atmosphere is then a consequence of those processes.
Since energy in must equal energy out at ToA it must follow that after deducting the solar energy throughput the remaining net energy flux up or down within the atmosphere must be zero.
If there is no additional energy flux through the atmosphere then GHGs cannot slow it down or speed it up.
The upward radiative effect of GHGs must exactly balance the effect of GHGs in blocking upward longwave for a zero net effect.
Indeed that principle must apply to all causes of opacity in the atmosphere.
The concept of radiative flows up or down within an atmosphere over and above the basic solar throughput must be wrong.
All the ‘extra’ energy in an atmosphere is simply a haze of infrared which stays in situ unless the non radiative processes also change speed.
There appears to be a flux because of reducing density with height which causes the lapse rate whereby temperature declines with height but all that is really happening is that KE is being converted to PE as one goes up through the column.
The actual energy content of every molecule from surface to ToA remains exactly the same when both KE and PE are accounted for.
Roy’s model fails because in a gaseous atmosphere there can be no solid obstacles. Even if there were they would only disrupt the flow of solar throughput which would indeed lead to a rise in system energy content.
Roy is comparing apples with pears.
Where there are no solid obstacles there will be no net flux within the atmosphere other than that arising from the throughput of solar energy.
The radiative characteristics of constituent molecules will have no net effect on energy throughput.
Stephen rather than just snipping your comments, I want to ask you:
The solar energy you correctly say is transferred from the surface to the atmosphere through conduction and convection…does all of this energy input just keep accumulating endlessly in the atmosphere?…Why does the atmosphere not increase in temperature endlessly?
You do realize that you can’t keep pumping energy into a system (the atmosphere) without it also having some way of cooling itself to maintain some reasonable temperature, don’t you?
No it doesn’t keep accumulating.
It gets recirculated constantly, surface to atmosphere and back again.
People are having problems accepting the ‘back again’ part.
One has to understand that all descending air warms adiabatically because as it descends PE changes to KE which is a warming effect.
That is what keeps the surface warm, not DWIR.
Solar energy goes straight through. Atmospheric energy is constantly recycled.
It first got there when the atmosphere formed when the presence of the atmosphere caused a short delay in the throughput of solar energy.
It was mass that caused that delay,not radiative characteristics and the energy was taken up into the atmosphere by conduction and convection,stored as PE and then recycled ever since.
So, in your scenario, the daytime convective heating of the atmosphere ends up going back into the surface at night? Gee, how does that happen when the surface almost immediately becomes cooler than the subsoil in the evening? Sounds like one of those 2nd Law violations to me.
The warmed descending air only slows the rate of cooling. It doesn’t need to impart energy directly though it can do so such as during warm surface winds across cold landmasses and that happens on a continental scale.
The scenario you refer to involves little or no wind.
Globally areas with little wind are small and very temporary so your scenario is not representative of the average.
In that case the fast rate of cooling of the surface often leads to a temperature inversion but the warmer air aloft still inhibits the total amount of cooling that can occur.
The cooling of the surface stabilises when fog condenses out in the colder layer because the fog absorbs energy directly from the warmer air aloft, or when cloud forms aloft at the inversion layer.
It isn’t the cloud radiating down. It is the warmer layer in which the cloud floats that inhibits radiative loss by radiating down.
If there is little or no humidity an inversion layer with clouds or fog is less likely to form and instead the descending warmer air can reach the ground and will be cooled by the surface to its dew point which deposits what little humidity it has as dew on the ground. In that case the latent heat of condensation is imparted to the ground to reduce its rate of cooling. When frost occurs the latent heat of fusion reduces the rate of ground cooling.
In dry still air the descending warm air carries little latent heat which reduces the extent to which the descending air can restrain cooling so then the surface can get very cold despite the KE from the dry descending air.
But still,taking a global average, the downward flowing KE (converted back from PE in the descent) doesn’t warm the surface it just causes it to cool more slowly as per your own scenario.
Taken globally, all that is enough to raise temperatures by 33C by slowing the cooling of the surface.
It is all a matter of the behaviour of atmospheric mass using non radiative energy transfer mechanisms and not radiative characteristics.
Roy,
Whilst I agree that ‘back radiation’ will have an effect in the slowing of the surface, like Stephen I cannot see how it can have as much effect when compared to direct heat transfer by conduction/convection. As I mentioned in a post below a typical domestic heating system in Europe is based on warming air through conduction and convection from hot water radiators and the resulting heated air warms the environment primarily via conduction….the air being the transport medium for the heat. There must be radiation involved but I believe it is miniscule in comparison to conduction. Similarly, the dynamics of the earths surface heating can be more adequately described, as Stephen has in this and other posts, by conduction and heat transport by the atmosphere. Intuitively it feels like radiation is being overplayed and rather than being a primary driver in the way the troposphere transports heat and warms the surface, it is primarily constrained to being a means of the energy escaping (just like in a house that is fully insulated); obviously in the instance of the Earth the only means of escaping. I note from various surveys that there is a large percentage of meteorologists that are skeptical of AGW and I suspect this disconnect, between their understanding of the dynamics of the atmosphere and that projected by climate scientists, is at least partly to blame.
Dr. Spencer – I think Stephen Wilde is driving at the same point presented by Gerlich & Tscheuschner (2007) “Falsification Of The Atmospheric CO2 Greenhouse Effects Within The Frame Of Physics”. In your experiment you have warm and cold plates which are constrained to make no physical contact with the warm plates. What happens to your experiment when the plates are brought into contact with the warm plates? Which method of energy transfer dominates: radiation or conduction? Now compare your plates with the atmosphere: how are solids different from gases? Correct: gases inter-diffuse and in so doing, introduce another method of energy transfer. That method is convection. Your experiment takes great lengths to minimize both conduction and convection. Why? Isn’t it because conduction and convection energy transfer effects would overwhelm radiative energy transfer effects and thereby ruin your experiment? The mean free path of particles in the lower atmosphere is very short, which means energy transfer by conduction & convection dominate our climate system. This is why your theory of cloud and storm formation governing climate change has such importance in the debate. The upper atmosphere has far fewer particles, longer mean free paths, and radiative energy transfer dominates (i.e. from the upper atmosphere to space). Anyway, I’m a big fan, and will continue checking in with you on occasion. I wonder if anyone estimating the energy transfer associated with solar wind has factored in the effect of reducing the upper atmospheric mean free paths of particles? That is, reducing the total LWR during solar max?
The earth’s atmosphere radiates IR energy back to earth and to deep space. Radiant transfer is driven by difference of the 4th power of source and sink absolute temperatures. So, degree K, sky to earth is something like 283^4 – 263^4. Sky to space is 283^4 – 4^4. That is a big brake on rapid climate change.
“Will the hot plates cool at different rates?”
Of course they will. Those who do not grasp this should definitely stay inside in winter as they do not appreciate the function of their living room walls.
Spencer,
I’m afraid this experiment wouldn’t resolve anything. We all agree the hot plate facing the cold one would cool faster than the hot plate facing the ambient one. That’s a no-brainer. But it also isn’t the apple of discord. At all.
Firstly, the hot plates are not constantly powered. They actually cool. Secondly, the experiment is conducted in a convective setting (i.e. not in a vacuum, where heat transfers only by way of radiation, but in air). Thirdly, the plates have significant thermal mass and conductive resistance.
The first point alone does in fact render the whole experiment moot even before being run. The other two would leave your results, and particularly your interpretation of them, on shaky ground. Especially mistaking conductive/convective effects for radiative ones is a notoriously easy trap to let oneself fall into. Fourier as well as Arrhenius did do just that. As do modern day experiment bloggers like TheFordPrefect. (Read about his various experiments to prove ‘back radiation heating’ and realise that the minor warming observed (from what I’ve seen, always well below 1% of absolute temperature increase after equilibration, when according to theory, from pure radiative flux, it should’ve been 20-40 times that) is clearly derived from obstruction in various ways of the movement of heated air away from the heater itself, you will see that his work is really rather building a pretty solid case for the ‘no heating from back radiation whatsoever’ position.)
Your first point does not render the experiment moot. You don’t need a steady state system to demonstrate the that different temperatures will result in different radiative cooling rates.
Your second point…yes, the heated plates will lose heat from conduction and convection, as I mentioned. If anything, that will reduce the radiative impact I am looking for because the plate which cools less radiatively will end up making up for it with convective loss. But the plates could be sealed in with Saran wrap to reduce the effect.
The third point, the plates having thermal mass, is immaterial to demonstrating that one plate would cool faster than the other. We are looking for differential effects here. Less thermal mass and higher thermal conductivity would, presumably, be better.
But it is true that it is difficult to make an experiment that demonstrates the physics of the greenhouse effect, and your comments give me some idea of the objections that will arise.
That’s why I say the thermal imager looking at the sky is actually the most direct evidence of the greenhouse effect, since it directly measures surface temperature changes (of the microbolometer surface) in response to varying levels of downwelling sky radiation.
Roy W. Spencer, Ph. D. says, May 16, 2013 at 1:05 PM:
“Your first point does not render the experiment moot. You don’t need a steady state system to demonstrate the that different temperatures will result in different radiative cooling rates.”
My point was, that this proposed experiment does not resolve any disagreement. Because there is no disagreement on what you’re trying to show here.
What you need is an experiment that demonstrates that an object constantly powered/heated after equilibration is then significantly heated beyond this steady ‘input temperature’ when an object cooler than the warm object, but warmer than the surroundings is placed next to it (or even better, surrounding it). And such an experiment needs to be conducted in a vacuum chamber, because any restriction of conductive/convective heat loss from the surface of the powered object would cause it to heat up.
It is the radiative effect we’re after …
yes, that would be the best demonstration, I agree.
Kristian, you mean the “Yes, Virginia” experiment, right?
http://www.drroyspencer.com/2010/07/yes-virginia-cooler-objects-can-make-warmer-objects-even-warmer-still/
I’m pretty sure a microbolometer measures voltage changes in response to the energy flux through the sensor, positive changes are marked as higher temperatures than the sensor, negative changes are marked as lower temperatures than the sensor.
You’ve stated repeatedly that a microbolometer is warmed by IR from colder objects, this is utterly false, it is not detecting temperature changes of the sensor, only voltage changes.
Your “evidence” is nothing of the sort.
That’s like saying thermometers do not measure temperature they just measure the volume of mercury in an enclosed glass container.
There is no doubt that everyone expects the hot plates to cool at different rates.
Of course they will.
But your headline
“How Cool Objects Can Keep Warm Objects Warmer Still”
Is a very odd way to put it.
It implies that cool objects can make warmer object warmer still.
Its clear that you don’t expect the warmer plates to increase in temperature.
They will cool at different rates.
But the headline can be interpreted that way.
There is ambiguity of language which is in nobodies interest.
Yes, I use that language in the title to tweak the Slayers, who claim that by the very nature of their lower temperature, cool objects cannot cause warm objects to be warmer still. If this was true, you wouldn’t use more blankets to stay warmer at night.
The drawing away of heat from a heated surface by way of convection CAN be physically inhibited.
The escape of the radiative flux (EM energy waves of a certain frequency spectrum) from that same heated surface, however, can NOT be physically inhibited.
If you then say that the ‘back-radiated’ flux cannot stop the outgoing from leaving, but is instead adding to the energy of the heated surface, raising its temperature that way, then you are in effect saying that the back radiation provides extra HEAT to the surface.
This is what you need to explain, to expand on. Because this is the crux of the matter. What do you actually mean? How is this NOT a violation of the second law?
Either the outgoing radiation IS directly and physically restricted (it is not). Or the incoming (back-radiated) radiation is adding HEAT to the surface. Only along these two paths could we actually achieve an increase in the equilibrated temperature of the heated surface.
The second law does not say that a cooler object cannot emit IR energy in the direction of a warmer object. If you think it does, you are trying to extend the second law beyond how it has been stated.
That’s because the second law does not deal with emitted IR radiation at all. It concerns itself with heat (and work). Energy that travels across system boundaries. Heat and work are one-way flows or drifts, like the electric current between high and low voltage. Heat flows solely because of a temperature difference between two systems. Not because of their radiation.
Kristian: You don’t understand what “heat” is. Heat is a net macroscopic flow of energy. Hence, you have no clue what the 2nd Law says or doesn’t say. Worse yet, you have no clue that you have no clue, so you fancy yourself in expert about something you know absolutely nothing about.
Great argumentation, Joel. As always. Not addressing at all what I’m actually saying. But lots of bluster and cocksureness to make up for it. That’s why you’re such an uninteresting person to ‘debate’ with. Less bombast, more substance, please.
Joel. Heat is as much a ‘net’ flow of energy from high temperature to low as wind is a ‘net’ flow of air from high pressure to low. The second law of thermodynamics deals with heat. Not with electromagnetic radiation. Heat only travels one way. How does the cooler atmosphere transfer heat to the warmer surface to make it warmer still, Joel? Or does the ‘back radiation’ simply physically block the outgoing radiative flux? Oops, so much for your upward 390 W/m^2 …
Kristian,
As we have explained to you a thousand times, the cooler atmosphere doesn’t heat the warmer surface. The sun heats the warmer surface. The surface gets warmer still because its temperature is determined by having to balance the heat it receives (from the sun) and the heat it emits (to the atmosphere and eventually out into space).
And, the 390 W/m^2 is the amount emitted by the surface. It is not the net radiative transfer from the surface because indeed the atmosphere transfers from radiation back. There are two equivalent ways of looking at it: I can either say that the Earth emits 390 W/m^2 and the atmosphere emits 333 W/m^2 back or I can say the net radiative transfer from Earth to atmosphere is 57 W/m^2.
Let’s say that I pay you $1000 and then you pay me $800. We could either characterize it this way or we could say in net, I paid you $200. Is this that difficult a concept to grasp?
You’re meticulously avoiding the issue, Joel. It’s plain to see. You’re desperate not to address it directly. Waving, waving. Over here, over here. Frankly it’s a bit sad to see.
I’m asking you specifically to explain HOW the atmosphere radiatively ‘reduces the cooling’ of the surface without itself transferring HEAT to the surface.
Is its ‘back radiation’ flux physically inhibiting the outgoing radiative flux from the surface, a direct result of its acquired temperature after having absorbed the heat flux from the Sun, forcing the solar incoming to raise the surface temperature some more?
Or,
Is the ‘back radiation’ flux (the atmospheric incoming) adding energy directly to the surface, raising its temperature that way?
Please answer this, Joel. Don’t beat around the bush.
How is your adding of the 324/333 W/m^2 not adding heat to the surface? How is this flux not what’s doing the extra warming? If the temperature rises when you add this energy, there is no way around it, you’ve turned this energy into heat.
Joel Shore is partly but not completely right. He rightly says that the gross radiative transfer from the land-sea body is about 390 W/m^2. But not all of that is absorbed by the atmosphere. Some of it passes directly to space between the clouds, perhaps about 40 W/m^2. The other 350 W/m^2 is absorbed by the air and clouds. If the radiation from clouds and air to the land-sea body is about 337 W/m^2, then the net radiative transfer from the land-sea body to the atmosphere is perhaps about (350 – 337) W/m^2 = 12 W/m^2.
Of course Kristian is muddling meaning of the word heat. It has two meanings. One is the ordinary language one, increasing the temperature of a body; this usage leads to muddles unless it is carefully noted. The other meaning is passing energy to a body by a mechanism other than work; this is the meaning used in physics; it refers to net transfer, not just to transfer of a radiative moiety. The ‘back radiation’ is passing energy to the land-sea body, but does not raise its temperature above its value that actually determines the emission, its actual temperature. It “raises its temperature [ordinary language usage of ‘heat’]” only virtually, relative to a hypothetical value that it would have had without the ‘back radiation’; this is not an actual raising of temperature, such as is implied by Kristian’s muddled word usage. Properly speaking, the atmosphere transfers a moiety of energy to the land-sea body, but such a moiety is not a heat transfer in physical terms, because a physical transfer of heat is a net transfer, not just a moiety transfer.
Kristian,
As I noted before, you do not understand the definition of the word “heat”…Please see this post where I discuss your misunderstandings: http://www.drroyspencer.com/2013/05/a-simple-experiment-to-show-how-cool-objects-can-keep-warm-objects-warmer-still/#comment-80073 It is only after you invest a little time learning physics that we can have a productive conversation. [You are speaking from ignorance. There is nothing inherently wrong with ignorance. Everyone is ignorant about some subjects and the good news is that ignorance is curable with knowledge…But ignorance combined with arrogance tends to be incurable because the arrogance prevents the absorption of knowledge.]
“How is your adding of the 324/333 W/m^2 not adding heat to the surface?”
Because more energy flux is going the other way, so the net macroscopic energy flow, i.e., the heat is from the surface to the atmosphere. If energy could not escape at all from the Earth and it received energy continuously from the sun, its temperature would increase without bound. (It is an impossibility to set this up in principle and get a temperature for the Earth hotter than the sun only because the laws of radiative transfer tell us that there is no way to engineer an atmosphere that can prevent heat from escaping while still allowing solar through, hence naturally enforcing the 2nd Law.)
So, it is not the atmosphere that is adding heat to the surface. It is taking heat away from the surface…but much less efficiently when the atmosphere has a lot of opacity in the IR than when it is transparent in the IR. You need a higher temperature at the Earth’s surface to successfully radiate the energy back out into space for the same reason that you need a higher pressure in a narrow hose in order to get the same volume flow rate of water out as in a wider hose.
Joel Shore says, May 17, 2013 at 9:01 PM:
““How is your adding of the 324/333 W/m^2 not adding heat to the surface?”
Because more energy flux is going the other way, so the net macroscopic energy flow, i.e., the heat is from the surface to the atmosphere.”
Exactly. So how is the surface temperature then raised radiatively by having a cooler atmosphere (i.e. one that draws heat from it) on top of it?
“So, it is not the atmosphere that is adding heat to the surface.”
Yes, so you claim.
“It is taking heat away from the surface…but much less efficiently when the atmosphere has a lot of opacity in the IR than when it is transparent in the IR.”
This is where the sophistry begins. Yes, it is taking heat away from the surface. But much less efficiently … OK? How? This is the simple question I’ve been asking you now for some time and which you still refuse to answer. You rather seem to avoid it at all costs.
How exactly is the free escape of outgoing thermal radiation from the surface (in your world, the 390 W/m^2) (a function of its absorbed HEAT and hence temperature) inhibited by the ‘back radiation’ from the atmosphere?
It is not inhibited. Your whole point is that the 390 W/m^2 go out no matter what. (Just as the 240 W/m^2 would freely escape the surface as radiation before you put GHGs in the atmosphere (same albedo). Purely a function of temperature.)
What you claim is that (most of) this free upward flux escaping the surface toward the atmosphere is however subsequently absorbed and partly sent back as a ‘counter flux’ to the surface (in your world, the 324 W/m^2).
In other words, there is now extra energy added to the surface.
Well, then. If the absorbed heat from the Sun is always free to escape the surface again unhindered as thermal radiation, purely as a function of the resulting temperature, then how is the surface temperature radiatively raised? If not by the Sun (assumed constant), then by what?
Your only remaining option is the 324 W/m^2 of ‘back-radiated’ energy from the atmosphere.
OK. So if the surface temperature rises when this energy is added and all else (Sun/surface) is equal, then tell me how this energy transfer does not constitute a transfer of HEAT from cooler atmosphere to warmer surface?! Exactly what you said the atmosphere didn’t do.
“It is taking heat away from the surface…but much less efficiently when the atmosphere has a lot of opacity in the IR than when it is transparent in the IR.”
I’ll correct that for you, because it’s actually mostly correct:
“The troposphere is taking heat away from the surface … but much less efficiently when the atmosphere is heavy (massive) than when it is light (less massive).” The atmosphere restricts free convective and evaporative heat loss from the surface, its main heat loss mechanisms, by being massive and pressing down on the surface.
“You need a higher temperature at the Earth’s surface to successfully radiate the energy back out into space for the same reason that you need a higher pressure in a narrow hose in order to get the same volume flow rate of water out as in a wider hose.”
No. You need a higher temperature at the Earth’s surface to successfully carry the absorbed surface heat convectively up and away (ultimately to the tropopause) to be radiated back to space. The troposphere is in effect a heat conductive layer between the surface and the tropopause, where convection represents ‘the conductive flow’. Thermal radiation is mostly along for the ride. Until the convection top. It just is. A function of temperature.
# The escape of absorbed heat from a heated surface by way of molecules (conduction, convection, evaporation) CAN be physically restricted.
# The escape of absorbed heat from a heated surface by way of EM energy waves (‘photons’, thermal radiation) can NOT be physically restricted.
That’s the gist of it all.
Joel Shore says, May 17, 2013 at 9:01 PM:
“Kristian,
As I noted before, you do not understand the definition of the word “heat”…Please see this post where I discuss your misunderstandings: http://www.drroyspencer.com/2013/05/a-simple-experiment-to-show-how-cool-objects-can-keep-warm-objects-warmer-still/#comment-80073 It is only after you invest a little time learning physics that we can have a productive conversation. [You are speaking from ignorance. There is nothing inherently wrong with ignorance. Everyone is ignorant about some subjects and the good news is that ignorance is curable with knowledge…But ignorance combined with arrogance tends to be incurable because the arrogance prevents the absorption of knowledge.]”
Dr. Spencer. Why do you allow this person to continue spewing out such utterly condescending ad hominem drivel?
“It is not inhibited. Your whole point is that the 390 W/m^2 go out no matter what. (Just as the 240 W/m^2 would freely escape the surface as radiation before you put GHGs in the atmosphere (same albedo). Purely a function of temperature.)”
No…It is not 390 W/m^2 no matter what. If there were less GHGs in the atmosphere, then the surface would be cooler because it wouldn’t need to radiate 390 W/m^2 in order to have 240 W/m^2 escape to space. In fact, if the atmosphere didn’t absorb any radiation, it would only have to radiate 240 W/m^2 and would hence have a lower temperature accordingly.
“Well, then. If the absorbed heat from the Sun is always free to escape the surface again unhindered as thermal radiation, purely as a function of the resulting temperature, then how is the surface temperature radiatively raised? If not by the Sun (assumed constant), then by what?”
The temperature is raised because the temperature is determined by the condition that the Earth has to radiate back into space the same amount of radiation as it receives from the sun. This thus depends not only on how much radiation it receives from the sun but how easily (i.e., what surface temperature it has to maintain) to radiate 240 W/m^2 back out onto space.
“OK. So if the surface temperature rises when this energy is added and all else (Sun/surface) is equal, then tell me how this energy transfer does not constitute a transfer of HEAT from cooler atmosphere to warmer surface?! Exactly what you said the atmosphere didn’t do.”
Because the net macroscopic flow of energy is still from the Earth to the atmosphere. If I get paid $1000 per month and I give my landlord $500 of it and then he lowers my rent and only charges me $400 per month, then do we say that the net flow of money is now from my landlord to me?
“The troposphere is taking heat away from the surface … but much less efficiently when the atmosphere is heavy (massive) than when it is light (less massive).” The atmosphere restricts free convective and evaporative heat loss from the surface, its main heat loss mechanisms, by being massive and pressing down on the surface.
Heaven help us! The mass of the atmosphere does not in any direct way effect the amount of energy that the Earth can emit to space (other than things like the pressure-broadening of the absorption lines of the GHGs).
“No. You need a higher temperature at the Earth’s surface to successfully carry the absorbed surface heat convectively up and away (ultimately to the tropopause) to be radiated back to space. The troposphere is in effect a heat conductive layer between the surface and the tropopause, where convection represents ‘the conductive flow’. Thermal radiation is mostly along for the ride. Until the convection top. It just is. A function of temperature.”
Now, we are at least making progress in that you are understanding that the Earth has to radiate back into space the 240 W/m^2 that it receives from the Earth and the convective transport mechanism that you have identified is an important way that it can transport heat up into the atmosphere to be radiated away. However, the problem with the convective mechanism is that it only goes so far: The atmosphere is only unstable to convection if the lapse rate is larger than the adiabatic lapse rate. Hence, convection can only drive temperature difference between the surface and the upper atmosphere down so much. If this were not the case and convection can drive the atmosphere all the way to an isothermal structure then this would indeed get rid of the radiative greenhouse effect…but it can’t, so it doesn’t.
“# The escape of absorbed heat from a heated surface by way of EM energy waves (‘photons’, thermal radiation) can NOT be physically restricted.”
This is the sort of utter nonsense that any introductory physics textbook tells you is incorrect. The net macroscopic flow of radiated energy, i.e., the heat radiated by an object, depends on both the temperature of the object and of the surroundings. If the surroundings are warmer, then indeed the heat flow is less. There is ample experimental evidence to interpret this affect as arising from the fact that the objects radiates out to the surroundings but that the surroundings also radiate back to the object, a statement you will find in all those same introductory physics textbooks…although even if you don’t adopt that correct interpretation of what is happening, it doesn’t change the equation itself.
Kristian,
I think it is telling that you find that so condescending and “ad hom”. If you were self-aware enough, we wouldn’t have to point this out to you. But, you seem to lack the self-awareness to realize that it is perhaps possible that you might not know as much about a subject that you have clearly never studied in comparison to people who have spent years studying it.
Apparently, you consider yourself to be so overwhelming brilliant that you can be an expert on the 2nd Law even though you haven’t studied any of the physics that underlies it.
I guess I am always puzzled by people like you because I never have that sort of brazen overconfidence to believe that I know a lot about subjects that I have essentially never studied.
Congratulations, Joel!
Quite an impressive post, I must say. You managed to spin every single paragraph you quoted. It only takes a cursory look to understand that you’re not here to discuss what I’m actually writing, but rather to obfuscate and detract from it as much as possible. You are not this stupid, Joel. A grown, educated man, a physicist at that, does not so completely ‘miss’, unwittingly twist and warp simple opposing arguments like this.
But thanks for showing your true colours.
You’ve clearly got absolutely nothing but rhetoric and bluster, so … bye.
Joel Shore says, May 18, 2013 at 7:32 PM:
“I guess I am always puzzled by people like you because I never have that sort of brazen overconfidence to believe that I know a lot about subjects that I have essentially never studied.”
Haha! Good one.
Wow. What insight. What modesty.
Roy says
“Yes, I use that language in the title to tweak the Slayers”
But that’s not what its all about!
Folk like Kristian and myself who have come up via the Carnot, Clausius route think that the second law is not merely about more net energy moving from hot to cold.
Its about the quality of the energy.
Can the frequency spread of photons from higher temperature sources initiate certain physical events more probable than with lower temperature sources?
Folk working on solar cell improvements have realised this and their literature is full of phrases like;
Energy Quality
Entropy
Exergy
Its good that Joel has widened the discussion with the
example of finance
He says
“Let’s say that I pay you $1000 and then you pay me $800. We could either characterize it this way or we could say in net, I paid you $200. Is this that difficult a concept to grasp?”
Lets say in 2007, A invests all his money in property and by 2013 has lost 50%
His neighbour B instead invests all his money in bank shares and loses 80%
Can we then say that the property market has made A wealthy?
This is analogous to the climate science use of language.
No…The analogy would be with the Slayers who would say (assuming both A and B started with the same amount of money) that we can’t say that A is now richer than B because it is impossible for A to be richer than B because its impossible for a losing investment to make A richer.
Joel is right. A is not richer, but he got poor slower. I don’t see the difficulty in seeing that if A went outside he might cool more slowly due to IR radiation bounced back by the atmosphere.
I believe (almost) everyone is sincere in their opinions here. I happen to agree with Roy, Joel and others that IR radiation is scattered by the atmosphere and slows cooling. I admire the patience of Roy, Joel and the others that are trying to explain their position (over and over).
Perhaps an agreement to disagree is in order and the conversation should move to other topics.
Bill and Joel
Yes an investment that loses money does not make you ‘wealthier still’ even though other investments can lose money at a faster rate.
Likewise an GHG atmosphere does not make the the night land surface ‘warmer’ or even ‘warmer still’.
Even though the land surface would lose heat more rapidly if there was no atmosphere.
Yes, it does because the Earth is also heated from the sun. And, the temperature is determined by the steady-state condition that the heat it radiates back out into space much equal that which it receives from the sun.
Joel …..I specifically picked night conditions
“make the the night land surface ‘warmer’ or even ‘warmer still’.”
This was to make the situation simpler and more like Roy’s post above dealing only with a cooling object.
Bryan,
I don’t see how night or day really changes it…The basic idea is that the average temperature is higher in order to maintain radiative balance.
Bryan,
I agree with both your statements above. Radiation scattered by the atmosphere does not add heat to the earth’s system, it merely delays the heat’s escape to space. The portion reflected back to the surface delays that heat’s escape to space. Whether that is thought of as adding energy to the surface or slowing the cooling of the surface, I think, not important and not different – except for the point of view.
As for the second point, on an earth without an atmosphere we wouldn’t be having a discussion.
Interesting experiment. If I had to bet, I’d bet the “hot plate” closest to the “cold plate” will cool faster than the “hot plate” closest to the “ambient temperature plate”.
Possible ways (and combinations thereof) to improve/modify the experiment.
(1) Use thermocouples to measure plate temperature.
(2) Reduce the experimental set up to a single “hot plate” and a single “not hot plate”. Run the experiment twice. The first time, set the temperature of the “not hot plate” to 0 F. The second time, set the temperature of the “not hot plate” to the ambient temperature. By doing this, you remove potential issues of differing plate emissivities.
(3) Enclose the set up in a vacuum. Depending on the quality of the vacuum, this removes most conduction heat loss and all convection heat loss. Furthermore, you no longer need the Styrofoam or the polypropylene. If you enclose the set up in a vacuum, make an attempt to keep the temperature of the vacuum enclosure at a constant value–say by using material with high thermal conductivity.
General Discussion
I agree with you that the presence of inert objects (objects with no internal source of thermal energy) at temperatures lower than a “hot object”, will, relative to the absence of those cooler inert objects, influence some thermal properties of the “hot object”. If the “hot object” is itself inert, the primary effect will be to alter the time-rate-of-change of the temperature of the “hot object”–i.e., change the rate of “hot object” cooling. If the “hot object” is active (i.e. has a constant internal source of thermal energy), the primary effect won’t be to reduce the rate of hot object cooling, but rather to change the energy-rate-equilibrium temperature of the “hot object”. [Energy-rate-equilibrium is defined here to be the condition that the rate thermal energy enters an object (or any part thereof) is equal to the rate thermal energy leaves the object (or the designated part thereof).]
However, even when radiation (often called backradiation) from the cold object to the hot object exists, for both the “inert hot object rate-of-cooling” case and the “active hot object energy-rate-equilibrium temperature” case, the change induced by the placement of an inert cool object in the vicinity of a hot object may be positive or negative. That is, in the case of an inert hot object, the hot object rate of cooling may be increased (i.e., the hot object may cool more rapidly) by the presence of the cooler object even in the presence of backradiation from the cooler object to the hot object; and in the case of an active hot object, the energy-rate-equilibrium temperature of the hot object may be decreased by the presence of the cooler object even in the presence of backradiation from the cooler object to the hot object.
If the immediately preceding statement is true, although it is correct to say that an inert cool object will affect some of the thermal properties of a hot object, it is incorrect to claim that the presence of a cooler object that emits backradiation to a hot object will always result in either (a) a decreased rate of hot-object cooling or (b) an increased hot object temperature. Thus, the fact that atmospheric greenhouse gases backradiate energy to the Earth’s surface is by itself insufficient to claim that greenhouse gases will increase the Earth surface temperature. Bottom line, Dr. Spencer’s experiment directly relates to the claim that cooler objects can affect some of the thermal properties of hotter objects. At best, however, Dr. Spencer’s experiment only starts the discussion of whether cooler objects that “backradiate” to hotter objects will (a) in the inert hot object case, decrease the hot object rate of cooling, and/or (b) in the active hot object case, increase the hot object’s energy-rate-equilibrium temperature.
For two configurations identical in all ways but one, I now discuss (a) the rate of cooling of an inert hot object, and (b) the energy-rate-equilibrium temperature of an active hot object. In the case of the inert hot object, I argue that the presence of backradiation from a greenhouse gas will not decrease (in fact will increase) the rate of hot object cooling; and in the case of an active hot object, I argue that the presence of backradiation from a greenhouse gas will not increase (in fact will decrease) the energy-rate-equilibrium temperature of the hot object.
Both configurations use thermos bottles. A thermos bottle has three main parts: (a) an inner chamber whose walls hold matter whose temperature is to be maintained for as long as possible at either a higher or lower value than the surrounding environment, (b) an outside wall, and (c) a region between the inner chamber walls and the outside wall. In a vacuum thermos bottle the region between the inner chamber and the outside will is a vacuum. In a CO2 thermos bottle, the region between the inner chamber and the outside wall is filled with CO2 gas (a greenhouse gas). Configuration 1 is called the vacuum thermos bottle configuration. Configuration 2 is called the CO2 thermos bottle configuration.
Analysis of the inert hot object rate of cooling.
Place both thermos bottles in a large room whose temperature is everywhere the same. Fill the inner chamber of each thermos bottle with equal amounts of coffee at equal temperature greater than the room’s temperature. Monitor as a function of time the temperature of the walls of the inner chamber.
In the CO2 thermos bottle case, the heated coffee will warm the walls of the inner chamber which will then both radiate and conduct heat to the CO2. The heated CO2 will radiate energy in the IR band in all directions. Some of the CO2 radiated energy will be directed back towards the walls of the inner chamber. If it’s true that backradiation always decreases hot object rate of cooling, the time required for the inner chamber walls of the CO2 thermos bottle to reach room temperature will be greater than the time required for the inner chamber walls of the vacuum thermos bottle to reach room temperature. Furthermore, by increasing the amount of CO2, the amount of backradiation is increased. Thus, the more CO2 we put into the region between the walls, the lower we expect the rate of cooling to be. I believe the opposite is true–i.e., the inner chamber walls of the vacuum thermos bottle will take longer to reach room temperature than the inner chamber walls of the CO2 thermos bottle.
Analysis of the active hot object energy-rate-equilibrium temperature.
Place both thermos bottles in a room whose temperature is everywhere the same. Fill the inner chamber of each thermos bottle with equal amounts of coffee at a temperature greater than the room temperature. Insert into the coffee in both thermos bottles a battery/resistor electronic circuit that generates thermal energy at a constant rate. When all material has reached energy-rate-equilibrium, measure the temperatures of the inner walls of both thermos bottles.
In the CO2 thermos bottle case, the heated coffee will warm the walls of the inner chamber which will then both radiate and conduct heat to the CO2. The heated CO2 will radiate energy in the IR band in all directions. Some of the CO2 radiated energy will be directed back towards the walls of the inner chamber. If it’s true that backradiation always increases the energy-rate-equilibrium temperature of the hot object, the temperature of the inner chamber wall of the CO2 thermos bottle will be higher than the temperature of the inner chamber wall of the vacuum thermos bottle. Furthermore, by increasing the amount of CO2, the amount of backradiation is increased. Thus, the more CO2 we put into the region between the walls, the higher the temperature of the inner chamber walls of the CO2 thermos bottle should become. I believe the opposite is true–i.e., the energy-rate-equilibrium temperature of the inner chamber walls of the vacuum thermos will be higher than the energy-rate-equilibrium temperature of the inner chamber walls of the CO2 thermos.
If I’m right, backradiation from atmospheric greenhouse gases to the Earth’s surface is NOT BY ITSELF sufficient to claim that atmospheric greenhouse gases will increase the Earth’s surface temperature. It may well be that atmospheric greenhouse gases increase the Earth’s surface temperature relative to the absence of greenhouse gases, but backradiation from those greenhouse gases by itself is insufficient to make that case.
some good comments here. Of course, most people (not even me) have a vacuum chamber to do experiments with.
Also, it should be noted that experimenting with even pure CO2 in a vacuum bottle or other limited space will have very little effect on the broadband IR transmission through it because the path length is too small.
This is one reason why demonstrating the greenhouse effect experimentally is so difficult…it takes thousands of feet of atmosphere to cause a substantial influence on broadband absorption/emission.
A spaceborne radiometer looking down might measure 240 W/m2, while a ground based instrument looking up might measure 100 W/m2 more than that…but that 100 W/m2 differential is over the entire atmosphere, originating mostly in the lowest 10-20 km or so.
“This is one reason why demonstrating the greenhouse effect experimentally is so difficult…”
As I said in the last post, a solar pond is a better demonstration.
I heard that the mean free path of IR at the band absorbed by CO2 is about 15 feet in the atmosphere. Your comment above implies a much longer distance. is that true?
A small change maybe?
“The main point is that cooler objects which surround heated objects affect the heated objects temperature”
You could point out that the surrounding objects temperatures would anyway affect the main object. No matter if they are cooler or warmer, it will only change the way it affects it.
You could change the polypropylene sheet with at highly reflectiv material and then observe that the backradiation (reflected) from the mirror delayed the cooling of the hot plate.
I wonder how Claes will twist this observation.
Claes has already weighed in, above.
Here’s an experimental suggestion:
Take an old-fashioned hot-plate or coffee warmer (http://www.amazon.com/USB-Cup-Warmer-Coffee-Mug/dp/B000K1V58A, $1.56, for example). Attach a thermometer to it with some heat-sink goop for good thermal connections, and put it inside a styrofoam box with a double-pane glass side. Make sure you can see the thermometer through the glass, and that the power cord comes out! This box prevents convection or conduction – only radiation exchanges through the glass.
Then, in whatever order you like, plug it in and let it come to equilibrium in a normal room (your living room, perhaps), then in a freezer. [ A walk-in fridge would be best, but depending on the size of your plate and box you might be able to manage it in your kitchen fridge. ]
Compare and contrast equilibrium temperatures.
A simple coffee-warmer can manage 50-60C at room temperature, so it’s hotter than its surroundings in both environments.
Prediction: The plate with a constant input energy (the cord, the equivalent of sunlight) will be warmer in the living room than in the fridge – warmed by objects (the walls) considerably cooler than it is. Repeat: the hot-plate will be warmer due to cool objects in its vicinity, much as the Earth is warmer due to the cooler atmosphere – via radiative exchange.
In an open system like this, and like the climate, energy in = energy out at equilibrium, energy radiated scales with temperature, and while considerably cooler than the hot-plate, the living room walls send more IR to the box than the freezer does – hence more incoming energy and a higher temperature to radiate that energy in the living room.
you would need to use something like Saran wrap, though…glass is opaque to IR, and so most of the heat loss will be by way of conduction through the glass.
Gah! Quite right, glass would be inappropriate.
Double-paned Plexiglass or Lexan would work as well – they have a decent transmittance for IR, and are in fact used as covers over IR remote control emitters.
I like that you try to explain the reality of radiation and have a little extra:
A very common observation from daily live is a proof of the existence of back radiation or lack of it.
Place yourself close to a cold wall (a wall to exterior winter time), and next to a warmer wall (to interior). You directly feel the cooling from the cold wall relative to the comfort near the warm wall. The common explanation is that the cold wall radiates cold, but in fact it is the lack of (back) radiation that makes you feel the cooling from the cold wall.
In normal indoor temperatures (20C) you have a radiation of 400W/m2, and 5K change means a difference of 20W which is easy to feel.
Yes, I know, and have mentioned this before, too.
Another experiment which proves the GHG effect is real, and needs to be dealt with if anyone wants to get a handle on the climate situation.
It is good to see the Dr Spencer is at last banning the dragon guys. They wave their hands but do not talk right physics, and they perhaps mislead some readers. It would be good if they took this action of Dr Spencer as a guide, that they need to learn some real physics.
Probably redundantly for many readers, I would like to make a comment about the choice of Krylon flat white #1502 as a coating for the metal plates. I am no expert on paints, and so for the moment I will just quote http://www.infrared-thermography.com/material-1.htm . It says there that Krylon flat white #1502 has an emissivity of 0.992 at 3 micrometers, and of 0.989 at 10 micrometers. That makes it suitable for the present experiment. That is to say it is a good approximation to a thermodynamically defined black surface at those wavelengths, which are relevant ones for this experiment, which is dominated by infrared, not visible, radiation. That it gives a flat appearance also makes it suitable, because that makes it close to Lambertian, another essential property of the thermodynamically defined black surface. But I think it may be useful to point out that its whiteness refers to its appearance at visible wavelengths, which are a step removed from the infrared wavelengths of this experiment, at which it appears black in the thermodynamic sense.
It may also be useful for some readers to consider why it is appropriate to use a coat of paint to set the emissivity of the surfaces of the metal plates. Don’t the plates have their own emissivity, and constitute the bulk of the emitting material? Wouldn’t that determine their emissivity?
Planck answered this. He proposed a good model for this situation. He pointed out that at an interface such as is relevant for the present experiment, between a near vacuum (the air) and a body of condensed matter (the metal plate), there is reflection and passage of radiation, but that the surface itself is not a physical emitter or absorber of radiation: it is just an abstract geometric object where reflection and passage of radiation is decided and takes place. To a good enough approximation for the present comment, the present experiment is nearly enough under conditions of thermodynamic equilibrium. That means that nearly enough, inside the metal plates, the radiation is black-body radiation at the temperature of the plates. What comes in and goes out, across the interface, to the contiguous air, is determined by the reflectivity of the interface. The reflectivity is the same when viewed from inside the plate as when viewed from outside it; this is called the Helmholtz reciprocity principle; it was partly recognized by Stokes in 1849, and fully by Helmholtz in 1856 (see http://vlp.mpiwg-berlin.mpg.de/library/data/lit39509/index_html?pn=181&ws=1.5), used for the analysis of experiments by Balfour Stewart in 1858, and explicitly quoted in theoretical work by Kirchhoff in 1860. The statement that the “emissivity” of the interface is 0.992 really means that the reflectivity of the interface is 0.008. The “emissivity” really means that the fraction of the radiation that passes through the interface has that value, 0.992, not that the interface itself emits or absorbs the radiation. Only 0.008 of the radiation, either inwards or outwards, is reflected. It is much easier to measure reflection at, than passage through, the interface.
Roy: Several people here seem to be objecting to your experiment on the grounds that it deals only with rates of cooling and not causing an object to have a higher steady-state temperature. So, here is a discussion of an experiment performed around 1800 by Pictet: http://www2.ups.edu/faculty/jcevans/Pictet%27s%20experiment.pdf What he did was put a thermometer bulb at the focus of a parabolic mirror and then something cold (snow) at the focus of a facing parabolic mirror quite far away (so the conduction and convection were not an issue). When, he put the snow at the focus of the 2nd mirror, the temperature registered by the thermometer dropped significantly, but only if the container of snow was well-placed at the focus. He also experimented with making the snow colder by pouring nitric acid on the snow and saw that this lowered the temperature registered by the thermometer further.
It is nice because it deals specifically with radiation and it specifically shows how the stead-state temperature of the thermometer bulb is affected by the temperature of the object radiating toward that bulb.
[By the way, credit goes to Rosco for making us aware of this experiment in another thread here http://www.drroyspencer.com/2013/05/time-for-the-slayers-to-put-up-or-shut-up/#comment-79613 , although he strangely thought that it somehow supported his Slayer point-of-view.]
By the way, see p. 741 of the article I linked to for Pictet’s own description of the experiment and result. Also note that there is a discussion of our modern understanding of what the experiment demonstrates on pp. 749-750 and then also a discussion of how to reproduce the experiment.
If the thermometer is attached to something being actively heated, e.g. by electricity or laser, the experiment would come closer to satisfying Kritian’s criterion, i.e. that the test object actually increase in temperature when irradiated by a cooler object.
Rosco’s misinterpretation of the Pictet experiment, however, suggests that even this wouldn’t convince some people.
It is actively being heated by its warming surroundings, so I don’t really see how that is much different than being heated by the sun. The point is that it is a case where a colder object doesn’t just slow the cooling of a warmer object…It causes the steady-state temperature of that warmer object to be warmer than it would be under other circumstances. (Not that Kristian or Rosco are likely to be convinced…because their objections aren’t scientific objections; that’s just the masquerade.)
Yes, I see your point. Kristian, for example, concedes that Dr. Spencer’s experiment would work as expected, while not realizing that he’s demolished his entire case.
But explicitly, ostentatiously, and flamboyantly heating the measured object in the Pictet experiment would at least remove one of Kristian’s “objections” to Dr. Spencer’s proposed experiment–that the test plate isn’t constantly heated–and force him to come up with a new and hopefully more entertaining excuse. 🙂
Gary Hladik says, May 16, 2013 at 6:32 PM:
“Kristian, for example, concedes that Dr. Spencer’s experiment would work as expected, while not realizing that he’s demolished his entire case.”
Gary,
From the very beginning (on WUWT) you proved to us all, again and again, that you did not comprehend what this issue is and is not about and what I was and was not asking you to provide, even though you proudly and repeatedly avowed that you did do exactly that, even ‘probably better than [me]’ making the request in the first place.
You do not disappoint. You’re still flaunting your strangely confused perspective on this matter.
You (and the rest of you people) have yet to locate one single problem or discussion addressing even remotely the ‘heated object warming its heat source’ issue. That is all I want for you to produce. ONE physics and/or engineering case where a constantly heated object after temperature equilibration is then radiatively made even warmer by the introduction of an object cooler than the heated object, yet warmer than the general surroundings. I am not asking for examples where the radiative cooling (or heating) rate of an object is changed by a cooler object. That’s NOT the issue, Gary. I’m asking for examples showing that such a change will radiatively make a constantly heated warmer object warmer than its initial, equilibrated temperature, that is, without the cooler object, only heat source and (cold) surroundings.
THAT’S your central claim after all. We agree on the cooling rate thing. So you can stop flinging that around as some sort of proof of some other effect that we however apparently will simply have to deduce from this one by ourselves. But this ever non-discussed effect is exactly the one we’re after. THAT’S the one we don’t agree to: ‘The cooling rate thing making the warmer, constantly heated object warmer still by radiation’ thing. That is where the disagreement is to be found. And that is specifically the effect that is nowhere to be found outside the greenhouse realm.
Your utter confusion on the matter is neatly summed up in the following statement of yours (from a comment you made on another thread on this blog):
http://www.drroyspencer.com/2013/05/time-for-the-slayers-to-put-up-or-shut-up/#comment-79309
“If a cooler object had no radiative effect on the temp of a warmer object, the temp of the cooler object would be irrelevant and omitted from the equations.”
Gary. Hello!? Yes, a cooler object does have a radiative effect on the temp of a warmer object. IT COOLS IT! What it doesn’t do is WARM it. A warmer object would have that radiative effect on the temp of a cooler object.
Why are you making this so difficult. It’s not.
Gary,
In that specific comment linked to above, you’re still on about the thermocouple radiative heat loss problem that you first came up with on the WUWT thread some time ago as somehow proving your ‘case’. You simply do not understand that it in fact does the exact opposite, it proves that you have no case, that you’ve completely misinterpreted it.
Here’s the link you provided:
http://www.belgeler.com/blg/1k20/heat-chap-12-088
And you say: “Problems 12-88 and 12-89 deal with thermocouples and the error that can arise due to radiative cooling of the measuring bead. 12-89 shows how the addition of a radiation shield raises the bead temp closer to that of the gas being measured.”
This is comparable to the Pictet experiment, where you gullibly went along with the careful sophistry of Joel Shore that the setup was analogous to the Sun/Earth surface/atmosphere/space system and consequently felt free triumphantly to declare that what the atmosphere is doing is simply raising the surface (thermometer) temperature closer to that of the ambient air (the ‘heat source input temperature’).
Neither of you put too much thought into this, did you? It was all about rhetorically furthering your case.
Let me explain.
Radiative heat loss helps keep the surface cooler than it would’ve been with just the warm layer of air on top of it and only convection available for shedding heat. As does convection in place of radiation.
For thermocouples there are basically 2 distinct situations that can create significant error in the temperature reading.
Both the Pictet experiment (with the thermometer) and your thermocouple problems are examples of the first situation. And it will become obvious that this is NOT analogous to the Sun/Earth surface/atmosphere/space system after all. Quite the contrary.
2 different error situations:
1) The surface (thermocouple bead/thermometer) is warmed by the surrounding air through convection/conduction. As long as the air temperature (and hence the temperature of the surface) remains relatively low (like at room temperature), the increase in radiative heat loss from the surface as it warms will not significantly outdo the heat gain from the air through convection/conduction, so it will be able to very nearly reach the temperature of the surrounding air mass.
If a cooler reservoir is introduced (and focused, as in Pictet’s experiment) and/or if the surrounding air becomes vastly hotter (your thermocouple in a hot gas duct), then the T^4 exponential growth in radiative heat loss with temperature (and temperature difference) comes very much into play.
At this point you need to shield the radiation loss from the surface in order for it not to COOL too fast (radiative heat loss exceeding by a fair stretch convective/conductive heat gain).
This, however, is clearly NOT the situation at Earth’s surface. The Earth’s surface is not heated convectively/conductively by adjacent, warmer air, cooling by radiation only. It heats the adjacent, cooler air. Earth’s surface is rather like the second situation (with even larger potential errors):
2) A surface surrounded by a relatively cool gas, but warmed by a hot radiative heat source from a distance (like a fire), making the surface WARMER than the surrounding air, in turn radiating and convecting heat to it.
In this case what you need your radiation shield for is not to reduce the OUTGOING radiative heat loss, but to reduce the INCOMING radiative heat gain. In Earth surface terms, a solar shield.
This is exactly what our atmosphere is doing radiatively. It reduces the incoming radiation from the Sun (by 45%) while letting the surface cool adequately by thermal radiation, simply corresponding to the temperature induced by the absorbed radiative heat.
So you see, in situation 1) the surface ends up COOLER than the surrounding air because of enhanced radiative heat LOSS outdoing the convective/conductive heat gain.
In situation 2) it ends up WARMER than the surrounding air because of enhanced radiative heat GAIN, the radiative heat loss simply following (a function of) the heat gain.
In the former we thus need to shield the OUTGOING radiation to reduce radiative heat loss. In the latter we need to shield the INCOMING radiation to reduce radiative heat gain.
The situation at the surface of the Earth is obviously of the second kind. In this situation, the radiation going out from the surface could never exceed the radiation coming in. It would rather strive to reach its level, to keep pace. We see this every day: solar heat IN increases from dawn, temperature and hence radiative heat OUT as a result start increasing shortly thereafter, same the opposite way. No physical, observational evidence whatsoever of any direct restriction to heat loss by radiation (if you don’t count the incessantly asserted effect of the ’DLR flux’ as physical, observational evidence of course). It simply is whatever it needs to be, doing its job to cool the surface. No more, no less.
In situation 1) radiative heat loss overwhelms the heat gain from convection/conduction (because of its T^4 relationship flux/temperature) and hence the surface cannot reach the temperature of the surrounding air. A very different condition indeed.
Kristian says: Why are you making this so difficult. It’s not.
Heh heh. Right back at ya, Kris. 🙂
One last question I don’t think you’ve ever answered:
If your view (or the “Slayer” view in general) of physics is actually consistent with established science, why has nobody disproved the so-called “greenhouse effect” experimentally, e.g. with the “Yes, Virginia” experiment or one like it? If, as you claim, everybody “outside” climatology knows better, why have none of them earned fame and adulation by freeing humanity from the fear (and expense) of thermageddon?
This ought to be good. 🙂
If as you claim the thermometer ‘is actively being heated by its warming surroundings’ (like the Sun), then why doesn’t the thermometer get warmer when the new and cooler object (the bowl of snow) is introduced? If the thermometer in your opinion is constantly heated already, then why on Earth doesn’t the ‘extra’ flux from the bowl make it even warmer? It now receives energy from the surroundings AND the bowl …
Could it perhaps be because the bowl is colder BOTH than the thermometer AND the surroundings? That the only way the thermometer would not cool, but rather warm, would be if the bowl contained hot soup or something to that effect instead, i.e. that it was warmer both than the thermometer and the surroundings … being an actual source of heat?
This setup lacks either a real hot reservoir or a cold one, or both, depending on how you see it? Either way, this makes its result interesting, but completely irrelevant to the actual issue at hand.
But you naturally insist on misrepresenting it, to further your ’cause’ (whatever it might be), claiming it proves something that it most definitely is not.
Quite telling.
The thermometer bulb is heated locally by conduction from the air around it. In the initial situation with no snow, over half the lines of sight from the thermometer bulb bounce off the first mirror, run parallel across to the second mirror, and bounce through the focus and then out into the warm surroundings. So in this situation the thermometer bulb is effectively surrounded by the room the experiment is set up in. When the ice is placed at the second focus, it blocks this view, and much of the radiation from it, emitting only a smaller amount of radiation corresponding to its lower temperature. When the nitric acid is added, the radiation from it reduces further and hence so does the bulb’s temperature. The thermometer is still being heated locally by conduction from the air, but because it is optically ‘surrounded’ by a much colder surface, it radiates more than it receives and it settles at a lower temperature. The fact that the nitric acid makes a difference shows that when the radiation from the ice changes so does the thermometer temperature, even though in both cases the ice is colder than the thermometer.
The local heating by conduction/convection isn’t constant, but because it increases as the temperature difference rises it can’t be used to explain the drop in temperature.
It’s a nice experiment and does demonstrate the principle, but I’ve seen slayers argue their way out of this sort of thing before. When you’re not constrained by any of the laws of physics, there’s nothing you can’t escape from.
–
By the way, a better way to prevent convection is to mount the plates vertically in a box, warmer above cooler, so the air gets stably stratified.
Nullius in Verba,
You (as the rest, it seems) is clearly not reading what your opponents are in fact saying. You’ve created your strawman version of ‘the Slayer argument’ and seem happy continuing to address this construct rather than the actual argument. Listen to what I’m trying to tell you, what John Millett says (May 16, 2013 at 10:47 PM) and what Max™ says (May 17, 2013 at 3:41 AM): “(…) what does this have to do with the claim that a colder object will lead to a warm object being warmer?”
The Pictet experiment does not show that a cooler object can make a warmer object warmer still. Neither does Spencer’s proposed experiment.
This discussion simply displays your (willful?) ignorance as to what the real issue, the objection is about. It is not about reduced cooling rates or enhanced heating rates. It is about whether or not a cooler object heated by a warmer object in any way can turn and function as a second, separate heat source to its own heat source, that selfsame warmer object, itself being provided by and equilibrated to a constant input from a different, original (and hot) heat source.
We want you to explain exactly HOW the cooler object indirectly warms the warmer one in this case by not adding to its heat GAIN, but rather by reducing its heat LOSS, when it surely can and does not physically inhibit the outgoing radiative flux from the warmer object, being a function of its original input and temperature. So how does the warmer object become warmer still …? If it’s through the addition of ‘back-radiated’ energy, then this would contitute a heat transfer from cool to warm.
Nullius in Verba says, May 17, 2013 at 3:33 AM:
“By the way, a better way to prevent convection is to mount the plates vertically in a box, warmer above cooler, so the air gets stably stratified.”
This would prevent any normal (and very minor) upward convective flow, irrespective of the plates themselves. It would not however prevent conductively warmed air from a hot plate to be advected away from it in the direction of the cold plate … In other words, it would do very little to alleviate conductive/convective heat loss/gain from/to the plate’s surfaces.
“You’ve created your strawman version of ‘the Slayer argument’ and seem happy continuing to address this construct rather than the actual argument.”
Yes. Because I can’t figure out what the slayer argument actually is from one moment to the next. The language is unclear, and definitions seem to shift with every comment. So I’m not bothering to even attempt it.
“It is about whether or not a cooler object heated by a warmer object in any way can turn and function as a second, separate heat source to its own heat source, that selfsame warmer object, itself being provided by and equilibrated to a constant input from a different, original (and hot) heat source.”
If you define “heat” as the net transfer of energy without doing work, then the answer is no. Nor is it claimed.
If you define “heat” as energy transferred by radiation, conduction, or convection, then we’re talking about whether a cooler object (plates at 0 F and 80 F) can transfer energy by radiation to a warmer object (plates at 150 F) thus slowing their cooling, that selfsame warmer object being provided by and initially equilibrated to a different heat source – the oven.
If you’re saying that the differences between this situation and the one you’re talking about are material, so that we agree on the answer in the case of the proposed experiment but wouldn’t if you altered it in a particular way, then we can discuss how we can do so. But what we need is a definitive experiment that can be done and demonstrated easily/cheaply on which our respective versions of physics disagree. Then we can test it, and find out which is right.
But when Roy tries to get people to make such specific predictions about experimental situations, all we get is waffle.
—
Radiated energy passes in both directions, the emitted power proportional to T^4. Hence the net energy transfer, which is what thermodynamicists call the heat, is proportional to the difference in fourth powers and always from the warmer to the cooler. As the temperature difference reduces the rate of heat transfer reduces to zero because the rates of energy transfer in each direction approach equality. When the bodies are at equal temperature, they both continue to radiate energy towards one another, but these quantities are equal, because the temperatures are equal, and hence the heat transfer, which is the net energy transfer, is zero.
Conduction works in exactly the same way. The vibrations of atoms and molecules continue to transfer energy in both directions, but more energy is transferred from the hotter end towards the cooler end than vice versa, so the heat transfer is all one way. At constant temperature, the molecules don’t stop their pushing, but the flows of energy in all directions are balanced.
You can use “heat” in the everyday sense, in which case the second law only forbids net heat transfers, or you can use it in the precise thermodynamic sense, in which case backradiation isn’t a transfer of heat – it’s only one component of one. But you can’t mix the two meanings.
Kristian says: “The Pictet experiment does not show that a cooler object can make a warmer object warmer still.”
Yes, it does. When the snow + nitric acid is at one focus and the thermometer bulb is at the other, the thermometer bulb is warmer than the snow + nitric acid. When the snow alone is at one focus and the thermometer bulb is at the other, the thermometer bulb is warmer than the snow AND also warmer than it was when the snow + nitric acid were at the other focus. Hence, a colder object has made a warmer object warmer still. We replaced the snow + nitric acid by the less cold snow and the temperature of the thermometer increased…Just like when we replace the cold of outer space with the less cold IR-absorbing atmosphere, the temperature of the surface of the Earth increases.
Of course, you will find an excuse to dismiss this evidence just like you find excuses to dismiss all evidence that contradicts your religious conviction.
You are always changing the bar on us. At one point, you claimed that you would change your mind if we could find a reputable textbook problem. I found exactly the shell model of the greenhouse effect discussed in one of the most popular physics textbooks used to teach thermal physics to physics majors…but you dismissed it (along with the more cursory discussions of the greenhouse effect in intro physics textbooks).
It is clear that no amount of evidence will ever satisfy you. Your opinion is not based on science and it will not be influenced by science.
I think what Kristian is trying to tell us is something like this:
If object “B” is radiatively heated above ambient temperature by actively heated warmer object “A”, then thermal radiation from B can’t raise A’s temperature any higher than the active heating would by itself.
On the other hand, if B is heated by some means other than radiation from A, for example if B is a thermocouple radiation shield in a hot flowing gas, then its thermal radiation CAN raise A’s temp higher than A’s active heating would by itself, e.g. the shielded thermocouple bead in the same gas.
In the Pictet experiment, the ice bath supposedly isn’t heated by the distant thermometer, so it’s perfectly free to “heat” the thermometer more than, say, a block of dry ice.
Kristian, is this a good approximation of your position?
Joel, do you have a link for the textbook example of “the shell model of the greenhouse effect”? It sounds familiar, but if I’ve seen it I didn’t keep the link.
I once found a textbook problem resembling Willis Eschenbach’s “steel greenhouse”, but unfortunately it only gives the solution without fully working it out. I haven’t found a solution manual for the book. ðŸ™
http://books.google.com/books?id=O389yQ0-fecC&pg=PA368&dq=radiative+transfer+concentric+sphere+9-23&hl=en&sa=X&ei=5baWUYmwLMK2iwLwxYHAAw&ved=0CDYQ6AEwAA#v=onepage&q=radiative%20transfer%20concentric%20sphere%209-23&f=false
Gary,
I agree that this does seem to be the latest position that Kristian has retreated to. Which makes me wonder what sort of accountant Kristian imagines Mother Nature to be…It must be mind-boggling to keep track of where the energy originally came from.
As for the link to the shell model, here it is, admittedly not in a lot of detail, but the basic results are there, including the new higher equilibrium temperature of the Earth that is predicted: http://books.google.com/books?id=c0R79nyOoNMC&pg=115#v=onepage&q&f=false (ignoring the Earth’s albedo in the calculation)
Thanks, Joel. Link saved. I was wrong, I don’t remember seeing that one before.
Joel Shore says, May 17, 2013 at 10:35 AM:
“Kristian says: “The Pictet experiment does not show that a cooler object can make a warmer object warmer still.”
Yes, it does. When the snow + nitric acid is at one focus and the thermometer bulb is at the other, the thermometer bulb is warmer than the snow + nitric acid. When the snow alone is at one focus and the thermometer bulb is at the other, the thermometer bulb is warmer than the snow AND also warmer than it was when the snow + nitric acid were at the other focus. Hence, a colder object has made a warmer object warmer still. We replaced the snow + nitric acid by the less cold snow and the temperature of the thermometer increased…Just like when we replace the cold of outer space with the less cold IR-absorbing atmosphere, the temperature of the surface of the Earth increases.”
Haha, this really goes to show what an incredible sophist you are, Joel. These two lines say it all: “When the snow alone is at one focus and the thermometer bulb is at the other, the thermometer bulb is warmer than the snow AND also warmer than it was when the snow + nitric acid were at the other focus. Hence, a colder object has made a warmer object warmer still.” Made my day! Wow. Just, wow. I know you know that this has got nothing to do with a cooler object making a warmer object ‘warmer still’. So why do you act like you don’t? Why are you playing obtuse?
Because, at what point in Pictet’s experiment does the cooler object make the warmer one (the thermometer) warmer than what it was before any cool object was introduced (regardless of this cooler object being 200K or just 1K colder than the thermometer), that is, with only its ‘heat source’ around? Hmm, I wonder. Could it be at the point where the cooler object is no longer cooler than the thermometer? When it’s actually become warmer. At the point when it can transfer heat to the thermometer and make it ‘warmer still’.
A cooler object will always work to make it (the thermometer) cooler, only more or less. A warmer object will always work to make it warmer, only more or less. A cooler object can never work to make the warmer thermometer warmer, only more or less. Why do you pretend that this is such a difficult concept to grasp?
Joel Shore says, May 17, 2013 at 10:35 AM:
“At one point, you claimed that you would change your mind if we could find a reputable textbook problem. I found exactly the shell model of the greenhouse effect discussed in one of the most popular physics textbooks used to teach thermal physics to physics majors…but you dismissed it (along with the more cursory discussions of the greenhouse effect in intro physics textbooks).”
First of all, I haven’t got web access to that book apparently so I haven’t seen it at all. Could you perhaps provide me with a screenshot or some other kind of image or copy of the page in question, so I can read it?
And secondly, I specifically noted already the first time I asked for examples (at WUWT), that this particular kind of ‘physical phenomenon’, the ‘further warming of a heat source by back radiation from the object it warms’ kind, IS ONLY FOUND WITHIN THE REALM OF THE GHE. Which was to say that I specifically didn’t need self-referencing descriptions or claims of the GHE to back up the the decriptions and claims of the GHE. That I can find myself, thank you. There is no lack of such. My point was that there is a compelling paucity of descriptions and discussions of the basic concepts upon which the whole GHE is said to rely. In fact, you cannot find them at all, anywhere else in physics. Where is the basic physics underpinning the GHE mechanism? Where are the real physics or engineering examples, problems, homework assignments, descriptions, explanations, diagrams, discussions, whatever, anything hinting at the reality of the claimed ‘physical (GHE) phenomenon’ mentioned above … outside the realm of the GHE itself?
I was pretty clear on this. Still, all you threw at me was exactly what I wasn’t asking for: General descriptions of the GHE, always safely sequestered from the actual physics (like TD or QM) being discussed elsewhere, no references whatsoever tying it to examinations of basic, real physical effects.
It clearly shows you’ve got nothing, Joel. Ties in well with your shrill, void ‘kickback’: “Of course, you will find an excuse to dismiss this evidence just like you find excuses to dismiss all evidence that contradicts your religious conviction.”
“Because, at what point in Pictet’s experiment does the cooler object make the warmer one (the thermometer) warmer than what it was before any cool object was introduced (regardless of this cooler object being 200K or just 1K colder than the thermometer), that is, with only its ‘heat source’ around?”
Kristian: We’ve explained this to you before. Outer space is very cold (radiatively…about 2.7 K) so when you introduce the IR-active atmosphere, you are introducing something that, while still colder than the surface, is way warmer than what was there before.
“First of all, I haven’t got web access to that book apparently so I haven’t seen it at all. Could you perhaps provide me with a screenshot or some other kind of image or copy of the page in question, so I can read it?”
I don’t have any easy way to do that, but any decent university library (or university bookstore perhaps) should have a copy available: Charles Kittel and Herman Kroemer, “Thermal Physics” (2nd edition).
“I was pretty clear on this. Still, all you threw at me was exactly what I wasn’t asking for: General descriptions of the GHE, always safely sequestered from the actual physics (like TD or QM) being discussed elsewhere, no references whatsoever tying it to examinations of basic, real physical effects.”
Safely sequestered from the actual physics, as in hiding in a textbook on thermal physics? You are just making ridiculous demands. And, we did find other basic examples, like multilayer insulation but we couldn’t find a problem worked out to your complete level of detail because most people assume that once they have explained how said insulation affects the heat flow, you can use conservation of energy and work out any basic problems involving it.
Joel and Roy,
You both should thank Rosco for providing rather convincing empirical evidence of what some call “back radiation” from a cooler to a warmer object and subsequent absorption by the warmer object. This bygone experiment in some ways demonstrates the effect more clearly than Maxwell’s limelight experiment and could save Roy unnecessary time and labor searching his home for plates, Saran wrap, etc.. Of course, if the rather obvious experimental results failed to convince Rosco, who apparently initially uncovered the experiment for this blog, then how many Roscoe clones will be convinced by Rosco’s own data research of past experiments remains to be seen.
Do you have a link for the “limelight experiment”?
Gary,
Some months, perhaps a year, ago a blogger provided a web-link to Maxwell’s writings that included the limelight experiment. Unfortunately, after perusing the information I did not keep the web-address. When I attempted to Google the information a website came up that provided a scanned in copy of several volumes of Maxwell’s research, but proved in-complete. After a cursory perusal I did not find it. You may attempt to find it yourself, on Google. I wish you good luck. However, since Maxwell conducted research in the century before last you may get better results at a library.
Personally, I’d like to have a complete set of his writings. Even though some of his ideas did not fully work out, his contribution to physics and mathematics make him one of the greatest minds in history.
Thanks, John. Is this it?
http://books.google.fi/books?id=DqAAAAAAMAAJ&dq=prevost%20theory%20of%20exchanges&pg=PA225#v=onepage&q=prevost%20theory%20of%20exchanges&f=false
I also found a diagram of the experiment on a Slayer blog, but linking to it apparently sends my comment into oblivion. 🙂
Gary Hladik,
The link you provided does appear to direct to the limelight experiment. Thanks for the link.
To All,
On reflection, the Pictet experiment fails to prove that radiation from cooler objects can be absorbed by warmer objects. Since warm air molecules in the focal region originally and subsequently radiate to the concave metal reflectors and thus to the other focal region containing the thermometer. The presence or absence of cool or colder snow/ice (with or without nitric acid) may only allow or reduce warmer air molecules in the region to radiate IR. For greater clarity and control, the experiment should be performed in a near vacuum to minimize extraneous IR noise/feedback.
To All,
Maxwell’s limelight experiment involved visible light not IR, but may prove instructive. However, it’s been a while since I ‘ve read it and will review to see if it really provides convincing evidence.
Designating the plates left to right as A, B, C, D, I predict plate B will cool faster than plate C. The effect may not be dramatic, however, depending on actual starting temperature, distance between plates, time to get hot plates out of the oven, etc.
Suggestions: Stand plate A in a shallow ice bath to keep it closer to 0 degrees during the experiment. Perhaps stand plate D in a shallow room temperature bath to help maintain its temperature. Of course it would require control runs with only plates B & C plus baths, but the saran wrap should minimize convection effects.
I also suggest using thermometers vs FLIR, as Slayers seem to be superstitious about FLIR. Better yet, could old-fashioned mercury thermometers be attached to plates B & C with the heat sink goop KR mentioned?
You might also try the experiment with only plates C & D:
Heat both plates in the oven, but take plate D out a minute or two before C, so D is cooler than C. When placed in the apparatus together, might plate C actually increase in temperature briefly? I suspect the plates would cool too quickly to show this effect, but if it happens, the Slayers have no explanation (if I understand them correctly).
And a semi-serious suggestion:
Vacation in Hawaii. While there, visit your colleagues at the Mauna Loa observatory. Perform the experiment on the mountain to reduce convective interference (altitude 11,135 ft, pressure ~.66 atm). It still won’t convince the Slayers, but you’ll get some fun out of it. 🙂
So many of these people are not going to change their minds nomatter what is presented to them. The people that don’t accept the GHG effect really have everything else all to hell when it comes to the atmosphere and the processes that are involved.
They come up with ridiculus explanations for the atmosphere and the processes that occur in order to try to show their thoughts about a lack of a GHG effect can be substanciated, and tied into their wrong conceptions about how the atmosphere works.
Again you can’t account for climate change without having an understanding and an acceptance of the GHG effect.
You don’t have to do experiment to prove Roy’s point. Just ask the Eskimos “do your ice igloo keep you warm?” I suppose their answer is not shocking to most people. It can’t be just their imagination.
I’m amused that some people here don’t seem to believe that radiation is escaping earth to space. What’s keeping them here? I thought they don’t believe in GHE. If radiation doesn’t escape earth, soon the ocean will boil from all that heat.
I keep getting these cool ideas for experiments …
* NASA has these huge vacuum chambers — entire experiments could be set up inside them.
* I used to work with Closed-Cycle Refrigerators (T= 10K, high vacuum, radiation shields). A experiment could be set up inside on of them.
* A weather balloon! Send a pair of heaters up (at night), one of which has a radiation shield.
* Hey, send them up on the space shuttle!
…
And then I realize — why in the world would anyone go to the trouble and time and expense of such things to prove such a fundamental idea. ðŸ™
And after that you realize: If some folks genuinely doubt this fundamental idea, why WOULDN’T they go to the trouble and time and expense of DISPROVING it, thereby earning fame, fortune, and (perhaps most important) the last laugh? 🙂
The proverbial light bulb just went on … I think I just came up with a cheap, easy, definitive experiment that could be done in any undergrad physics lab in the country!
Actually, it is literally a light bulb — a standard 60 W household bulb. It has a built-in heater surrounded by a very good vacuum and a high emissivity material (glass).
But run the light bulb at very low power — only a few volts and a few watts. This will be just enough to warm the filament a little bit above room temperature (100-400 C should be good. Then submerge the glass of the bulb into water at various temperatures while maintaining a constant voltage. The “back radiation” from the glass should change the temperature of the filament. A measurement of the resistance of the filament will give the temperature of the filament.
*************************************
A few details:
* Liquid N2 or dry ice could be used to get lower temperatures. An oven could be used to get higher temperatures.
* The resistance vs temperature curve could be calibrated with no electrical power. Measure at 0 C & 100 C (and maybe higher with an oven). This is not actually critical, since all we really need to know is that the filament cools when the bulb is submerged in cold water and warms when the bulb is put in boiling water.
* A four lead resistance measurement would be best so that resistance of the leads won’t matter.
*Keeping the voltage constant (rather than the current) would be a little more robust. So for example, when the bulb is submerged in ice water, the filament will cool, the resistance will drop, and the power to the filament will go UP. This means that even though the electrical power in has increased, the temperature STILL went down, highlighting the role of the IR radiation from the surroundings.
Dr. Spencer with respect, what a pointless experiment. It only confirms well understood and agreed to concepts.
If you want to expand it into something that might make your point (which I still disagree with) might I suggest;
1) replace your heated “slabs” with a couple of nice thick chucks of copper (maybe about 2 inches thick)
2) replace your “cold” plate with a single tinfoil sheet punched full of holes (lots of holes)
3) replace your “ambient” plate with several tinfoil sheets punched full of holes (not lots of holes, just several holes)
By doing this you might be closer to the HUGE disparity between the massive thermal capacity of the oceans versus the trivial thermal capacity of the “greenhouse” gases.
Then you need to modulate the heat content of the copper slabs with a nice amplifier (maybe an old stereo amp that nobody needs any more), perhaps at 20 Hz ?
Then if you image the “far side” of your “cold” and “ambient” plates you will see that they will follow the temperatures of your hot plates, with a delay, the “cold” plate will of course respond more quickly.
I guess some folks will never understand that radiation flows through a system at the speed of light, this matters, it affects the response time and the delay time (two different concepts).
I understand the GHE hypothesis, unfortunately it is incorrect when it predicts a “higher equilibrium” temperature. NONE of your examples have eliminated that disparity.
Explaining that “we can’t possibly demonstrate it because we need; a 10 km long vacuum chamber, etc. etc. etc.” does not help your case. Good old Al Einstein (no, not a personal friend) imagined an experiment that would prove his theory. Why the heck can’t you ?
Cheers, Kevin (ban me if you like, but it is STILL NOT WARMING)
“By doing this you might be closer to the HUGE disparity between the massive thermal capacity of the oceans versus the trivial thermal capacity of the ‘greenhouse’ gases.”
Except in the very tenuous outer reaches of the atmosphere, collisions between molecules happen in very short amount of time and the greenhouse gases are in local thermal equilibrium with the rest of the atmosphere.
“I guess some folks will never understand that radiation flows through a system at the speed of light, this matters, it affects the response time and the delay time (two different concepts).”
“Delay time” or “response time” are red herrings. There is energy constantly coming in and leaving the Earth system. The rates of these must balance…and if you make it more difficult for energy to leave, so less is leaving than is coming in, then the Earth will respond by heating up until the balance it restored. It is no more difficult to comprehend than narrowing down a tube with water flowing through it and finding that one needs a larger pressure difference to maintain the same flow as before.
Joel wrote;
““Delay time” or “response time” are red herrings.”
Perhaps, but a whole field of engineering has developed (i.e. electrical engineering) without regard to your wisdom about what is and is not a “red herring”. I suspect you posted your comment using a computer that works because an electrical engineer someplace figured out the difference
between “delay time” and “response time”.
Hey look over there, it’s a RED HERRING. How come nobody ever sees a BLUE HERRING ?
That field has developed to address different problems than the one being addressed here. A “red herring” does not mean that the ideas are not useful in any context; it means that they are not useful in the current context.
…To elaborate a bit more, a delay time is useful when you are talking about sending packets rather than a steady stream. So, yes, if the sun just sent a pulse of radiation and then stopped, the effect of GHGs would be just to delay the propagation of the energy back out of the system.
However, what we are talking about is a steady-state situation where energy is constantly flowing in and out…and so the RATE of energy flow in and out is vitally important.
Joel, the funny thing about a “delay time” is that you can only observe it when a “pulse” travels through a system. BUT that does not mean it goes away when the input is “steady state”. It’s still there, you just can’t see it.
The magical “GHE” is simply an optical/thermal delay line, it causes energy flowing through the system to be delayed by making multiple passes through the system at the speed of light.
A thermal insulator slows the velocity of energy (thermal) flowing through it, two different effects.
So if you stop for a second and think that the Sun is actually sending “packets” (aka photons) of energy through the system you might be able to learn something from other fields that see similar effects.
You are chasing a chimera, you just don’t know it.
Cheers, Kevin.
Joel wrote;
“So, yes, if the sun just sent a pulse of radiation and then stopped, the effect of GHGs would be just to delay the propagation of the energy back out of the system.”
Thank you for confirming my hypothesis that the “GHE” only acts as a delay line. I posted here in Feb 2012 the following;
The “missing heat” is currently travelling as a spherical IR wavefront that is “X+d” light years away from the surface. In this equation X represents the elapsed time since the sunlight arrived (i.e. 100 years for sunlight from 1912) and d represents the slight delay from the GHE and likely averages about 5 milliseconds. “d” is actually a statistical distribution which will of course have a different specific value for each photon travelling through the system. Some will bounce many times and take longer to exit, while others may not bounce at all and exit directly to space.
Please see my prior post about the CONTINUOUS PRESENCE of the delay line effect and the inability to observe it when the input is “steady state”. This is why electrical engineers study DC circuits FIRST and then move on to AC circuits.
You made my argument for me, thank you.
Now, as a homework assignment I suggest you study up on the “Temporal Response of an Integrating Sphere”.
Cheers, Kevin.
Joel, I did some of your homework for you;
http://labsphere.com/uploads/technical-guides/a-guide-to-integrating-sphere-radiometry-and-photometry.pdf
Read section 3.7……..
Quite a nice explanation of the differences between a Pulse and a Steady State input. And they use an electrical
engineering term; “the impulse response”.
Cheers, Kevin.
Kevin,
Here is your error. You say:
“The magical ‘GHE’ is simply an optical/thermal delay line, it causes energy flowing through the system to be delayed by making multiple passes through the system at the speed of light.
A thermal insulator slows the velocity of energy (thermal) flowing through it, two different effects.”
In fact, both a thermal insulator and the GHE do exactly the same sort of thing. Both have a relationship for the rate of heat flow that involves both the temperature of the hotter object and that of the surroundings. Hence, by making the surroundings warmer, you decrease the rate at which heat is flowing out of the system. In the case of an object being supplied by a continuous source of heat, it must warm until it again is emitting the same amount of heat as it is absorbing.
This is really basic stuff. As an engineer, I am sure you learned that if you have a pipe with water flowing and replace it with a narrower pipe, then you will have to have a larger pressure difference across the narrow pipe to get the same amount of fluid flow?
[One thing that you might be missing is the fact that there is a vertical temperature gradient in the atmosphere, so the radiation is not just delayed…There is less radiation emitted if the radiation that can escape to space is from a higher and thus colder part of the troposphere than if the radiation that can escape to space is from a lower and thus warmer part of the troposphere.]
Joel wrote;
“In fact, both a thermal insulator and the GHE do exactly the same sort of thing.”
NO, a thermal insulator slows the velocity (rate of forward progress, distance travelled per unit of time, etc.) of thermal energy travelling through a system. The GHE delays the flow of energy through the system by causing the energy to make multiple passes through the system at very nearly the SPEED of light.
A material is only an insulator (thermal) IF the velocity of heat through it is SLOWER than the material sourcing the thermal energy (the surface). Thus you wrap your water heater with fiberglass. If you wrapped it with copper your energy bills would soar.
Since the GHE allows energy to flow away/towards the surface at the SPEED OF LIGHT, it most certainly does not act as an insulator for the soils or water on the surface which have significantly slower speeds of heat.
Joel also wrote: “This is really basic stuff.” Thanks for that unnecessary gratuitous slap. And yes I do indeed understand the relationship between water pressure and flow. See a previous post explaining how all those folks using 20th century science measured the “back pressure” in the plumbing of railroad steam locomotives.
So;
1) you all have a hypothesis; it will get warmer because of the GHE
2) it sure as heck is not getting any warmer
3) folks with broader experience (beyond “really basic stuff”) are trying to help you understand alternative hypotheses
4) you respond not with any slight semblance of intellectual curiosity about other possible explanations of what’s happening, but you lecture them about “basic stuff” like how come the water shoots out fast from their hose nozzle.
I kindly supplied you with a reference regarding the “temporal response of integrating spheres”, a prime example of how you cannot discern the delay line effect when the input is steady versus a pulse. You responded with a mini-lecture about how my water hose works.
The funny thing about “really basic stuff” is that it often leads you to the wrong answer, and you convince yourself you really, really understand something. Then someone with a bit more understanding explains why you might be incorrect. You could read a bit more, or lecture them about their stupidity instead. You picked the lecture; you would have been wiser to read a bit more first.
Cheers, Kevin
Dr Spencer,
You predict well.
However, to echo earlier comments, the experiment will resolve nothing. The phrases “warmer still” or “the atmosphere warms the surface” carry the meaning “a contemporaneous increase in temperature” which induces legitimate objection but which the science doesn’t mean – and therein lies the confusion.
On the other hand there could be no objection to:
“The main point is that cooler objects which surround heated objects affect the heated objects temperature”.
Dulong and Petit demonstrated this in 1817, finding that the greater the temperature difference/potential/gradient between the objects, the faster the warm one cooled – as you predict for your experiment. This is straightforwardly explained as a one way transfer of heat from warm to cool as per thermodynamic laws.
What is contested is explaining the finding in terms of two-way mutual exchange of radiation between the objects as asserted by Prevost in 1792 without experimental validation then or since.
The rebuttal that radiation, not heat, is exchanged rendering the second law irrelevant falls short. The radiation from the cooler object results from a conversion of kinetic energy to radiative energy, a conversion which is reversed at the warmer object. Kinetic energy being heat, the overall result is transportation of heat from cooler to warmer, a violation of the second law.
Mr. John Millet,
The 2nd Law of Thermodynamics states: In any closed system the amount of energy unavailable for useful work must always increase.
Consider a closed system comprised only of two objects, one warmer and the other cooler. If a warmer object receives energy transported from a cooler object, please explain how in any finite time period the energy unavailable for useful work decreases and thus violate the 2nd Law of Thermodynamics. Remember in any finite time period the warmer object always emits/looses more energy than it receives from a cooler object. If their exists some scenario I’m not aware of wherein such energy transportation violates the 2nd Law of Thermodynamics please let me know. I’m honestly trying to comprehend why this constitutes a violation.
To Mr. John Millet,
Please note a point of clarification. In any finite time period a warmer object always emits/looses more energy than a cooler object by definition. How can it be possible in any closed system as defined above and in any finite time period for entropy to increase?
To Mr. John Millet,
It seems I did not clarify. Allow me to restate my clarification. In any finite time period a warmer object always emits/looses more energy than a cooler object by definition. How can it be possible in any closed system as defined above and in any finite time period for entropy to decrease?
John K,
Some interesting material as a basis for scenario formulation:
http://geosci.uchicago.edu/~moyer/GEOS24705/Readings/Carnot_article_1998.pdf
Hi John,
Thanks for the link.
John Millett is another person who doesn’t understand that the term “heat” refers to a macroscopic quantity. Apparently, some people’s understanding of thermodynamics is stuck in 1850.
Here are a couple of links for those who want to get their understanding of thermodynamics into the 20th century:
http://en.wikipedia.org/wiki/Entropy_%28arrow_of_time%29
http://preposterousuniverse.com/eternitytohere/faq.html
And, here, even in the Wikipedia page on “heat” are some relevant facts [http://en.wikipedia.org/wiki/Heat]:
“Transfers of energy as heat are macroscopic processes. The origin and properties of heat can be understood through the statistical mechanics of microscopic constituents such as molecules and photons.”
“Heat characterizes macroscopic systems and processes, but like other thermodynamic quantities it has a fundamental origin in statistical mechanics — the physics of the underlying microscopic degrees of freedom.”
The biggest problem here with people talking about the 2nd Law is you are trying to apply macroscopic laws to microscopic situations that they don’t apply to. Here is another article about the thermodynamic limit: http://en.wikipedia.org/wiki/Thermodynamic_limit
If you haven’t taken a course in statistical mechanics (and refuse to listen to people who have), you are unlikely to have a very well-rooted understanding of the Second Law (or thermodynamics in general)…You are basically stuck in the 19th century…except, it is worse than that because you are trying to apply principles from the 19th century at the microscopic level that they didn’t know about in the 19th century. So whereas, their understanding was just incomplete, yours is manifestly incorrect.
I simply don’t understand why this is a persistent source of confusion for people. I also don’t understand why so much attention is still being given to those with no elementary understanding of radiative transfer or thermodynamics (and whom, by the way, have zero influence amongst anyone except their own small group of maybe half a dozen people, so a remedy against widespread misinformation isn’t an excuse).
The greenhouse effect works by allowing the planet to radiate to space at a temperature colder than the surface. The occular manifestation of this phenomena is directly seen in any IR emission spectra in the IR, shown as a “bite” in the outgoing thermal emission curve (e.g., http://climatephys.files.wordpress.com/2012/06/upwelling_toa12.jpg).
This “bite” exists because the atmosphere is radiating to space at temperatures colder than the surface. The “bite” is with respect to the underlying Planck blackbody curves at Earth-like surface temperatures, which would approximate Earth’s outgoing energy flow in the absence of an intervening atmosphere. Since the total outgoing radiation is the area under the curve of these graphs, the “bite” means that for any given temperature, the addition of opacity reduces the outgoing flux to space, and the system has to warm up in order for the increased emission over the spectrum to balance what was taken out by the greenhouse gases.
All that people need to understand here is that absorptivity doesn’t depend too much on temperature, but emission does (varying strongly with temperature). The ability to absorb upwelling “high-temperature” radiation, and emit radiation at a much colder temperatures (and correspondingly weaker intensities) provides a very good heat trapping mechanism. This is why Venus looks as cold as Mars at IR wavelengths. Moreover, if the atmosphere were vertically isothermal, say by having some distribution of sufficiently strong solar absorbers, then the terrestrial greenhouse effect would collapse. This is also why low clouds don’t contribute much to the greenhouse effect, since they are radiating to space at temperatures much like the surface; from the top-of-atmosphere perspective, there is no need for the system to warm in this case because these clouds did little to reduce the efficiency with which the collective system is losing energy.
Thermodynamically, the greenhouse effect simply reduces energy loss rate and thus puts the actual planetary temperature somewhere in between the “blackbody radiating temperature” (for Earth, ~255 K) and the temperature of the stellar photosphere (for the Sun, ~6000 K). Luckily for us, it’s only a very mild greenhouse effect in a planetary sense.
I hope Dr. Spencer can allow me to respond to this after all pretty off-topic comment from Colose.
The CO2 ‘bite’ (and other spectral bites) has got nothing to do with surface warming. It is simply the radiative transmissivity signal of an atmosphere containing IR-absorbing gases.
The absorption of radiative heat from the surface by the so-called GHGs is minor to begin with (~26 W/m^2 according to T&K97). It warms the troposphere slightly, but of course not the surface providing the heat in the first place. Illustrated simplistically by a planet/shell model, the (absorptive gas) shell warms by absorbing the heat, but not fully and therefore it only emits half of the original flux up as thermal radiative heat loss. So what we ‘see’ is the 26 W/m^2 go up from the surface but only half (13 W/m^2) emerging from the TOA. The radiative rate of heat loss to space has been spectrally reduced by the presence of an IR-absorbing troposphere, because these are the bands where the absorbing gases ‘catch’ the upward radiative heat to make the troposphere somewhat warmer. And that is the ‘bite’. This reduction could however NOT make the surface warmer. The ‘caught’ radiative heat is simply part of the total heat that the surface provides to the atmosphere in the first place, maintaining its temperature.
So the bite does not tell us anything about the magnitude of total OLR emitted from the Earth system to space at any point in time, only the spectral distribution thereof. Total OLR balances (in the longterm) perfectly with the net incoming from the Sun anyway: More in from the Sun, higher surface temperatures, stronger convection/evaporation, higher tropospheric temperatures as a result, elevation of the so-called ERL by the lapse rate, and also of the tropopause, and increased OLR to space. This is what is observed in the real world. There is NO observed general reduction in total OLR at the TOA during the last decades of global surface and tropospheric warming. In fact, the opposite has been observed, the OLR simply increasing in step with the temperature.
There is no tropospheric holding back of anything. There is just the ‘constant’ budget balance. At steady state, there is no inherent heat transfer delay (the only delay is in Earth system response time when the solar input changes, and this delay in response is convective).
So, then, what mechanism fills in the ‘bite’? Why, convection of course. The convectional fluxes (conductive/convective and latent heat transfer from ground level to the tropopause). The kinetic (thermal) energy produced by the absorption (the 26 –> 13 W/m^2 not escaping as spectral radiation) is continuously being transported aloft by the convectional engine to be dumped to space as thermal (not spectral) radiation from (on average) higher up instead.
What forces the global surface temperature to be warmer than the ensemble temperature of the Earth system, is simply the mass of the atmosphere restricting its convective and evaporative heat loss.
No.
Hi Kristian,
You wrote:
“The radiative rate of heat loss to space has been spectrally reduced by the presence of an IR-absorbing troposphere, because these are the bands where the absorbing gases ‘catch’ the upward radiative heat to make the troposphere somewhat warmer. And that is the ‘bite’. This reduction could however NOT make the surface warmer.”
A warmer troposphere cannot make a yet warmer surface even warmer, but it can warm cooler surfaces such as hmm…maybe glaciers. I’m not a global warming propagandist, but strong evidence indicates extensive glacial retreat over the last several thousand years. Anything that increases atmospheric temperatures in the troposphere will help speed up glacial loss. To a risk averse human population frightened of even small change, many will be scared of a process that’s been going on for several millenia and now seems to speed up. An acquaintance visited Alaska and returned 3 years later too find massive loss of glaciers in the region she visited. Most people, including over paid academics and physicists on web-sites, remain unfamiliar with the earth’s geological history and become frightened or do know the history but seek to frighten the ignorant and gullible to line their pockets and obtain positions of power. The same old human drama.
H L Mencken said:
“The whole aim of practical politics is to keep the populace alarmed (and hence clamorous to be led to safety) by menacing it with an endless series of hobgoblins, all of them imaginary.”
It helps when menacing a population to be able to point at some half-truth.
Chris Colose,
Since the curves are balckbody curves, the areas under them are the maximum they can be. The widening of the “bite” due to increased opacity increases the area difference between the curves with and without GHGs. The difference is a measure of the atmosphere’s LW radiative energy stock, the increase in which raises its temperature and its emissive power to space, an immediate negative feedback. I don’t see how the “bite” can be interpreted as a reduction in OLR, requiring a countervailing increase in surface temperature.
Roy,
I’d agree with your prediction of the effect on the two heated plates.
It seems to me that the debate about back radiation is polarised around whether the ‘surface warms the atmosphere’ or alternatively whether the ‘atmosphere warms the surface’. Well from my observations I would suggest there is much of both going on.
Around the equator where the insolation is at it’s strongest there is evidently heating of the surface and this in turn results in a strongly heated atmosphere. The surface gives up heat by conduction and evaporation to the atmosphere but also, and most significantly, there is a reserve of energy that goes into warming the surface, particularly the oceans. However, when it comes to the parts of the Earth which get much less insolation the surface is largely warmed by the atmosphere. For example here in the UK we only get consistent heat when we have a high pass over. We may get odd periods during the year when the surface does the warming but generally speaking the atmosphere is doing the work which is why we are at the mercy of the jet stream. There is no warming of the oceans around the UK other than in the shallow waters and only then when we have been subject to a high for some period and even then only later in the summer.
What compounds the problem and generates further argument is that conduction by the atmosphere to the surface is largely ignored when to my mind it must be the primary mechanism. Look at a domestic heating system and that is actively warming the rooms and furniture through conductive/convective warming. There will be some radiative warming but as we all know from text books this is the least effective transfer method. I used to have a flat with overhead heating (yes….whoever thought of that needs shooting!)…anyway, point is that if I stood on a chair I could get my head very warm as the temperature a foot from the ceiling was 25C. If I got off my chair and relied on the radiation from that heated layer we would freeze. It had zero effect in comparison to conduction. We bought electric heaters. I know we are told that air is a poor conductor but everything is relative, and relative to radiation, the conduction of air is excellent!!. So advice to both sides is stop being so ‘all or nothing’ and consider if you could both be right in part!
As has been pointed out, what does this have to do with the claim that a colder object will lead to a warm object being warmer?
Know what is funny?
Reverse the layout, put two ambient temperature plates where the heated ones are, leave the cold plate as is, place a hot plate where the ambient was:
|Cold | Ambient || Ambient | Hot|
Wait for a while, then after measuring the temperature of the ambient plates, switch them so the cold side plate is where the hot side plate is and vice versa.
Better yet, have two extra plates prepared, a hot and cold.
|Cold A | Ambient A || Ambient B | Hot A|
Let the experiment run for a set interval, hour, half hour, 3 hours, whatever you want.
Then swap the arrangement to this:
|Cold B | Ambient B || Ambient A | Hot B|
See what I’m getting at?
I hope it is not too late to comment.
I agree with the effect predicted by Dr Spencer.
My idea is that in order to magnify the radiation effect vs the convection effect, it would be wise to arrange the plates horizontally, the hot plates being at the top of the box, and the cold / ambiant ones at the bottom (in fact 2 identical heat insulated boxes are needed, or if only one, the experiment is done first with the say ambient temperature plate and then with the cold one)
The downwelling of 300-400w/m2 of IR from different sources that Dr. Specer just recently provided is very very strong evidence that the GHG effect is real in my opinion.
To those here who think absorption depends on photon temperature….
Experiment says it does not.
The interaction of radiation and matter — quantum electrodynamics (QED) — is the best theory in existence.
Some of its predictions are verified to 11 decimal places, i.e. the electron’s interaction with a magnetic field (g-2).
The result in no way depends on the temperature of the source of the photon.
Your experiment is already described on this web page.
http://www.efunda.com/formulae/heat_transfer/radiation/calc_2bodies_enclosure.cfm
It even includes a calculator to determine the answer.
What does that have to do with CO2???
Warm plate = earth’s surface
ambient plate = IR sources in the atmosphere (inhcluding CO2)
cold plate = outer space
The earths surface will cool slower with CO2 in the atmosphere than it would with an atmosphere that is completely devoid of CO2. The experiment is most akin to earth at night. To simulate the daytime, there should be a heat source into the warm plates.
Dr Roy.
Examining the initial conditions.
The board set 0F transmits 744.4 w/m2 and receives 240.5 w/m2 cooling at rate of 503.9 wm2.
The board set 80F transmits 744.4 w/m2 and receives 456.8 w/m2 cooling at rate of 284.6 wm2.
The cooling will be faster in the set 0F.
As for the explanation.
MAXWELL indicates that H=dE and E=dH while w=EH then a wave only generates heat when it encounters an obstacle that shifts the E and H fields one up the other.
I have an experiment that fits this theme.
http://www.scam.com.br/tjdavila/solo/quarta_lei_da_termodinamica.htm
D’Avila Tarcisio
Looks like an interesting experiment.
Any chance of an English translation?
My Google translator cannot cope with it.
Excuse me Mr. Bryan but I lost ascesso to this site.
I see that Roy has not followed through on my upthread exchange with him despite my having answered his questions satisfactorily.
So, with respect, may I now ask Roy to put up on two specific and simple issues.
i) Explain how the results from a pyrgeometer represent an indication of radiative flux in ANY direction when all it does is read temperature at heights that are dependent on optical depth. If the pyrgeometer were able to focus on open sky at the same height as a nearby cloud it would record a temperature the same as the cloud so switching between a cloud at one height and open sky at another height is NOT any indication of a different energy flux from cloud and open sky.
ii) Given the apparent lack of evidence of any additional radiative flux up OR down APART from the basic passage through of solar energy it appears that the additional radiation within an atmosphere is simply a static haze of IR graded as a result of the gravitational field placing greater density and therefore more KE at the bottom and more PE at the top. That vertically graded, static haze of IR would represent the radiative consequence of all the non radiative processes between surface and atmosphere netted out.
It follows that if there is no net upward or downward IR flux other than the basic throughput of solar radiation then the radiative characteristics of constituent molecules cannot either speed it up or speed it down without also changing the speed of non radiative processes in a full and complete negative system response.
The net thermal effect of the radiative characteristics of constituent molecules as opposed to mass must therefore be zero.
The non radiative response is adequately dealt with by the Gas Laws.
I submit that the entire ‘extra’ 33C heat at the surface of the Earth is fully accounted for by the IR haze created as a consequence of the non radiative energy exchange between surface and atmosphere.
Radiative physics has nothing to tell us about the greenhouse effect. The greenhouse effect is entirely a consequence of mass restrained by gravity and irradiated by an external energy source creating that IR haze around the planet as a by product of ongoing non radiative processes.
“Explain how the results from a pyrgeometer represent an indication of radiative flux in ANY direction when all it does is read temperature at heights that are dependent on optical depth. ”
No, a pyrgeometer reads neither “temperature” nor “at heights”. The pyrgeometer reads IR power flux at the location of the window on the top of he instrument. The instrument knows NOTHING about the heights from which the IR came — only that it did indeed arrive at the instrument.
This power flux can be converted to an “equivalent blackbody temperature”, but that will not particularly be the temperature anywhere above the pyrgeometer.
Roy has been quite clear on several occasions that the pyrgeometer measures the surface temperature of the target.
He also concedes that when pointed at open sky as opposed to a solid surface such as a nearby object the height of the point where the reading is taken depends on optical depth.
The optical depth of the cloud surface being greater than that of open sky so the temperature is taken at a lower, warmer height.
Perhaps Roy could comment on whether or not I misunderstood that ?
I’d also like to see him address the point that his claimed reason for a pyrgeometer working involves the sensor being warmed by IR from the target, when in fact it works by measuring the change in voltage through the sensor.
Positive changes suggest the sensor is gaining energy from the target, and thus it is warmer.
Negative changes suggest the sensor is losing energy to the target, and thus it is colder.
Quantifying those changes allows one to set a range of values corresponding to various temperatures.
______
If Roy was correct about his reasoning for the way microbolometers work then all microbolometers would have arbitrarily wide ranges and need no calibration beyond emissivity concerns.
Infrareed technologie.
http://www.hamamatsu.com/resources/pdf/ssd/infrared_techinfo_e.pdf
I suppose someone will try to suggest that radiative characteristics of constituent molecules can change the intensity of the IR haze but that runs into a problem with PV=nRT.
Increasing T without increasing P must result in an increase in V. P can only increase with more mass or more gravity which doesn’t happen because the extra mass in our CO2 emissions is not significant compared to total atmospheric mass.
An increase in V without an increase in P has a cooling effect as per the Joule Thomson Effect whereby the work done by the expansion opposing the intermolecular attractive force results in KE (heat) being converted to PE (not heat).
In order for PV to continue to equal nRT any rise in T caused by an increase in radiative capability of constituent molecules must be precisely offset by the cooling effect of the conversion of KE to PE during the expansion process.
Which is exactly the point I made in one of my earlier articles about the effect of adiabatic processes but at that time I was not aware that the phenomenon I was relying on was known as the Joule Thomson Effect.
In fact I have been making that point in different forms of words ever since 2008.
Yes, the radiative characteristics change the intensity of the IR haze, and no, that doesn’t cause any problems with PV=nRT.
The average pressure is simply the weight of the atmosphere above a unit surface area and so is effectively fixed at the ground. As T increases from, say 287 K to 288 K, the volume increases by 0.35%. The air at the bottom where it’s dense scarcely moves, the air at the top rises a little more, probably a few metres, although I haven’t worked it out exactly. (You should.) The potential energy gained is therefore at most a few tens of Joules per kg near the top of the troposphere. By contrast, the specific heat capacity of air is 1 kJ/kg.K, so increasing it’s temperature by 1 K takes around 1000 J/kg.
Not only that, but both changes are in the same direction, so they can’t offset one another. Warming the air both warms it and lifts it, so both KE and PE must increase.
That’s what I mean by sciency-sounding waffle. You can handwave over some babble about PE and KE and impress people who don’t know the physics well enough to estimate it for themselves, and who want to believe. But to a physicist it sounds incomprehensible nonsense, because disconnected concepts are alluded to vaguely with unbridged gaps between them. There’s talk of the constant-P case and the constant-V case, but then bits of each are mixed. And an adiabatic change is neither constant-P nor constant-V anyway.
You’ve been saying this since 2008? And it never occurred to you to check with anyone if it was valid physics?
“Warming the air both warms it and lifts it, so both KE and PE must increase”
Correct if the warming is a consequence of more mass, more gravity leading to more pressure and a higher density or a consequence of higher insolation.
Not correct for an increase in radiative capability of constituent molecules.
In that case warming doesn’t happen because the expansion (a cooling effect) is simultaneous with the additional energy absorption of the radiative molecules.
When acquiring that additional energy by absorption those molecules move apart so that the Joule Thomson Effect occurs and prevents warming.
The additional energy that is absorbed which would otherwise have resulted in warming goes straight to more PE instead of KE.
Stephen Wilde says: “In fact I have been making that point in different forms of words ever since 2008.”
And, therein lies the problem. Just speaking some words doesn’t cut it. You have to actually write down equations, because at the end of the day, a model defined by words, especially as people like you throw words around, is completely unconstrained. When skeptics like you (not sure if I have heard you specifically say it, but certainly many others have) say that models will give you any answer the modeler wants, they are correct if they mean models like the ones you come up with, which are never spelled out mathematically. However, mathematical models constrained by known physical equations actually do severely constrain things, which is one reason why real physical scientists use them.
As for the substance of your post, I explained mathematically here how the ideal gas equation plus the hydrostatic equation do not in any way constrain the surface temperature (or the temperature distribution at all): http://tallbloke.wordpress.com/2012/02/21/joel-shore-the-radiative-greenhouse-effect/comment-page-1/#comment-18180
See, actual math using known equations of physics…not a bunch of words that sound physicsy strung together (“babble” as Nullius in Verba nicely puts it).
By the way, in addition to the problems identified by Nullius in Verba with your scenario, there is a more basic problem, which goes back to the same mistake made by Nikolov and Zeller: You don’t understand how to apply conservation of energy to an open system.
When you have a system such as the Earth, which is receiving gobs of energy from the sun and radiating gobs of energy back out into space, you can’t think in terms of conserving energy on the Earth. Rather, the condition becomes one where the Earth system will adjust its temperature until it satisfies the condition that the energy coming in equals the energy going out.
So, all your musing about what sort of energies are involved in the expansion and so forth are irrelevant. What is relevant when you make a change in greenhouse gas levels is not how the system can re-adjust with zero energy going in or out. What is relevant is how the system can re-adjust so that there is again radiative balance between the amount of energy coming in and the amount going out.
Same reply as for Nullius:
Correct if the warming is a consequence of more mass, more gravity leading to more pressure and a higher density or a consequence of higher insolation.
Not correct for an increase in radiative capability of constituent molecules.
In that case warming doesn’t happen because the expansion (a cooling effect) is simultaneous with the additional energy absorption of the radiative molecules.
When acquiring that additional energy by absorption those molecules move apart so that the Joule Thomson Effect occurs and prevents warming.
The additional energy that is absorbed which would otherwise have resulted in warming goes straight to more PE instead of KE.
And the total energy content of the atmosphere (KE + PE) remains exactly as before.
“And the total energy content of the atmosphere (KE + PE) remains exactly as before.”
And there, you just prove to us exactly what we were pointing out, which is that you haven’t a clue how to apply conservation of energy to an open system. It’s okay to make that error once, but to be stuck in the same rut, by your own admission, for the last 5 years suggests that perhaps understanding basic atmospheric physics is not where your talents lie.
To summarise:
Solar radiation encountering a planetary surface for the first time will raise the temperature of some of the materials on the surface to cause a phase change from solid to gas.
As soon as the gas forms it will develop a circulation involving a variety of non-radiative energy transfer mechanisms.
In practice a gaseous atmosphere is usually present from the beginning due to internal energy from the formation of the planet.
A by product of the non radiative processes is a cloud of IR energy within the atmosphere and that energy becomes evenly spread from top to bottom of the atmosphere.
However the pressure gradient caused by gravity creates a density decline with height which allows higher gases to drift further apart thus provoking the Joule Thomson Effect whereby the available IR becomes graded into a slope with changing proportions of KE and PE.
PE does not register as heat hence the temperature decline with height.
So far everything has been achieved simply by mass held by gravity and irradiated from outside the atmosphere though a little internal energy will be present as well.
If one then changes radiative characteristics of constituent molecules then the affected molecules will simply rise higher if warmed or sink lower if cooled and the Joule Thomson Effect will adjust the proportions of KE and PE to those present at the new height with no effect on temperature or system energy content.
There will however be a climate consequence from a circulation change in the expanded or contracted atmosphere but too small to ever be measurable from our emissions.
Note that the expansion or contraction occurs where the GHGs are located and does not effect either pressure or density of mass at the surface which is why surface starting temperature (the intercept point) does not change.
That is the greenhouse effect and it is purely a by product of non radiative energy transfer mechanisms within an atmosphere.
It is a mechanical process, not a radiative process.
…And, it completely and utterly ignores how you apply the Law of Conservation of Energy to open systems, as I discuss above: http://www.drroyspencer.com/2013/05/a-simple-experiment-to-show-how-cool-objects-can-keep-warm-objects-warmer-still/#comment-80162
Please explain how you come to the conclusion that the Law of Conservation of Energy has not been applied.
At all times energy in at ToA and energy out at ToA are balanced subject to variations around the mean.
At all times the surface to atmosphere energy exchange is balanced subject to variations around the mean.
What do you think is missing ?
Stephen, maybe this exercise will help us all understand your position more precisely. One statement of the Law of Conservation of Energy say that the rate of change of energy within any region is equal to the energy into the region minus the energy out of the region. Since we are assuming a quasi-state-state situation with quasi-steady temperatures, then we can restate this as “the (average) net power flux through any surface will be zero”.
So apply this to three specific surfaces:
* The “ToA” (top of atmosphere) = some point above most of the earths atmosphere. For the sake of discussion, lets make this the tropopause.
* The “BoA” (bottom of atmosphere) = the boundary between the earth’s surface and the atmosphere
* The “MoA” (middle of atmosphere) = some altitude sort of half between ToA and BoA.
Give ball-park estimates of what fluxes go through a typcial square meter of each surface. For starters, here are my SWAGs (http://en.wikipedia.org/wiki/Scientific_Wild-Ass_Guess)
ToA: Net = +340 -340 = 00
IN:
340 W/m^@ SWR
OUT
100 W/m^2 reflected SWR
240 W/m^2 LWR
BoA: Net = +490 – 490 = 0
IN:
160 W/m^2 SWR
330 W/m^2 LWR
OUT
20 W/m^2 conduction/convection
80 W/m^2 latent heat
390 W/m^2 LWR
MoA: Net = +300 – 300 = 0
IN:
300 W/m^2 SWR (Some is absorbed higher up)
OUT
100 W/m^2 SWR reflected
60 W/m^2 conduction/convection
10 W/m^2 latent heat
130 W/m^2 LWR (much in the “atmospheric window, the rest via the “IR haze” that will be upward because of the temperature gradient).
****************************************
I’m not really interested in discussing the specific numbers I gave — they could easily be off +/- 20 W/m^2 or +/- 20%.
But give your numbers, Stephen. The net SWR in at the ToA, MoA and BoA will be ~ 240 W/m^2, ~ 200 W/m^2 and ~ 160 W/m^2 respectively. The other processes (whether you call them ‘net LWR’ or ‘adiabatic loop’ or ‘convection’ or ‘diabatic loop’) must equal the negative of these numbers.
There would be net zero radiative flux between surface and ToA apart from the basic throughput of solar energy.
The solar energy gets a free pass straight through in order to achieve ToA radiative balance.
All energy exchanges between surface and atmosphere are non radiative.
No need to look at separate layers within the atmosphere. The variations that do occur between the various layers get removed by the overall circulation so as to leave radiative balance at ToA.
So for example:
240 in at ToA and 240 out at ToA.
150 from surface to atmosphere and 150 from atmosphere to surface.
So one can have a temperature at the surface high enough to radiate 390 yet only 240 leaving at ToA.
In reality the extra 150 at the surface is not being radiated. It is being circulated constantly between surface and atmosphere by non radiative processes.
The temperature profile from surface is determined by the decline in pressure with height and not by radiative fluxes.
If one insists on looking at the surface / atmosphere energy exchange in solely radiative terms one could say that the topmost molecules of the surface radiate at 150 to the bottommost molecules of the atmosphere and vice versa but that is merely a consequence of non radiative processes right up through the vertical column and would only involve one molecule of depth in each of the surface and of the atmosphere.
Above that point right up to ToA non radiative processes are in command.
“In reality the extra 150 at the surface is not being radiated. It is being circulated constantly between surface and atmosphere by non radiative processes.”
In other words, you don’t particularly like the actual laws of physics, so you are just going to make up your own. And you expect us to take you seriously? The Slayers have nothing on you!
Tyndall-1861 show that atmosphere is opaque to IR and this make all diferent.
See http://tj.davila.zip.net for a demontration.
How de greenhouse effect work……
Sorry Stephen, but on this topic you are wrong, and Joel Shore is correct.
Please explain how you come to agree with Joel’s conclusion that the Law of Conservation of Energy has not been applied.
At all times energy in at ToA and energy out at ToA are balanced subject to variations around the mean.
At all times the surface to atmosphere energy exchange is balanced subject to variations around the mean.
What do you think is missing ?
Somebody is blowing smoke from the wrong hole.
Turn on a radio, any radio. Tune in a radio station, any station, AM, FM, makes no difference. You only hear one station, unless you happen to pick a station where there happens to be two stations on the frequency you pick, or within the pass-band of the frequency determining devices.
IR is an electromagnetic energy, just like radio waves are an electromagnetic energy. Please explain to me how the devices that Dr. Roy is using in these experiments differentiates between all of the different forms of energy (within the IR spectrum) and in essence only picks up “one radio station?” What prevents the devices from being affected by any other form of electromagnetic energy? Surely the sensor is not sophisticated enough to be immune to the effects of the harmonics of other energy. [Surely you have driven by the local high-power AM radio talk show station and heard the rants, or the CB rig of a passing big-rig “leak” through on your high dollar FM stereo?]
I also have trouble understanding how the sensor detects energy approaching 0 degrees K without the sensor at or below 0 degrees K. This does not seem to agree with what I was taught in college physics. Admittedly, that was 40 + years ago, has the physics changed since then? The display provided on an earlier post indicates that this detector is sort of like a Digital camera detecting IR energy. If so, at the distance of the troposphere, stratosphere, way out there, a single molecule of gas would cover a pixel on the detector, and the one on either side of it would be covered by another molecule somewhere up there, and the same for the pixel next to those. So you may have aimed it to “outer space” but it is looking at “inner space” regardless of where it is focused. Take the raw image from the most expensive camera you have and zoom in to 200, 500, 1000 as high as you can and you will quickly see just “fuzz.” Even a 16 Megapixel camera cannot differentiate good enough to do what Dr. Roy is implying with his shot of a house and clouds. I am not claiming that there is no equipment that can not determine what the temperature is, just that they do not have any “hand-held” equipment yet. And I believe that even it would have to take into consideration the effects of the temperature of the molecules in the atmosphere, just like astronomers have to contend with the light from cities masking stars.
UzUrBrain says: “Please explain to me how the devices that Dr. Roy is using in these experiments differentiates between all of the different forms of energy (within the IR spectrum) and in essence only picks up “one radio station?””
They DON’T differentiate all the different IR frequencies! That is the point. They have a “window” that reflects visible and Near IR, but lets through the mid-to-far IR. (Read up on “cold mirrors” http://en.wikipedia.org/wiki/Cold_mirror). The sensor is designed to INTEGRATE all of the pertinent IR, not to single out specific frequencies. It is picking up “all radio stations” to use your analogy.
“I also have trouble understanding how the sensor detects energy approaching 0 degrees K without the sensor at or below 0 degrees K.”
The incoming power is estimated using conservation of energy. The temperature of the face of the sensor is measured, so the outgoing IR can be estimated using Stephan-Boltzmann. There is also energy conducted to the face of the sensor from the body of the instrument — estimated with a thermopile (or simply by knowing the thermal conductivity of the materials involved). The difference must be the energy in toward the surface as IR.
SO if the body of the instrument is 300 K and it is aimed at 300K, the sensor will be 300 K. If it is aimed at 250 K instead, the sensor will cool below 300 K, since less IR is coming in. Aim it at 200 K, he sensor will cool even more. Someone just has to make a calibration curve by aiming the device at various known temperatures and then you can use that to find the temperature of other things .. even things down to 0 K in principle (although usually the calibrations don’t go down that low because the resolution would get very poor).
Here’s some I did earlier which may be of interest:
These first 2 attempt to show a iron green-house effect (using a single unwarmed plate to increase the temperature of a warmed body).
http://climateandstuff.blogspot.co.uk/2013/03/the-copper-greenhouse.html
http://climateandstuff.blogspot.co.uk/2013/04/the-copper-greenhouse-new-test.html
A cool object reduces the heat loss from a hot object
http://climateandstuff.blogspot.co.uk/2013/03/a-cool-object-reduces-energy-loss-from.html
I have been working on this one and have shown a more definite difference. However maintaining a constant ambient is a problem (need better than +-0.2°C
The improvements are better thermal insulation, a constant temperature cool object, and hopefully simultaneous multiprobe temperature measurements.
Criticisms and suggestions are welcome!
Yes, I saw those. Good work.
Now all you need is a vacuum chamber! 🙂
I’m baffled how you can use the same picture from a textbook which I used as evidence against this effect: http://2.bp.blogspot.com/-TpYh7VNmHnM/UVjX07FfakI/AAAAAAAABDk/TJEKeKHOILM/s1600/sphere+problem1.jpg and claim it supports the steel greenhouse case.
Heh heh. That’s the “classic” Problem 1023 discussed in a thread at WUWT. Here’s a Google link (page 20):
http://books.google.com/books?id=dQGC0ifkE34C&q=1023#v=snippet&q=1023&f=false
Kristian used it to break the First Law of Thermodynamics by inventing “anti-energy”. 🙂 THAT was a thread to remember!
http://i341.photobucket.com/albums/o396/maxarutaru/bunnytaru/lol%20censorship/heatsourceinshellatequilibrium_zps1c9d662a.png
I pulled this screenshot from that book at the end of last march.
http://i341.photobucket.com/albums/o396/maxarutaru/problem1026image_zpsa559d601.png
That is actually a shot from me posting it in that WUWT thread.
I was thinking of the comment thread to this April 24 WUWT article:
http://wattsupwiththat.com/2013/04/24/spencer-slays-with-sarcasm/
Where Problem 1023 showed up again.
Yeah, I posted them over at Joe’s site on 3/31, over at TB’s as well, though I forget when exactly.
I do know that the screenshot tfp used was the same one I pulled from that book.
Gary Hladik says, May 19, 2013 at 5:59 PM:
“Kristian used it to break the First Law of Thermodynamics by inventing “anti-energy”. THAT was a thread to remember!”
No, Gary. You used it to flagrantly break the Second Law of Thermodynamics by letting the inward J1 from the cooler shell warm the central warmer sphere, remember? The J from the sphere goes out anyway, reaching the shell, so how does the sphere become warmer if not for the inward J1?
(The 1st Law applies to single systems, Gary, not to double systems in interaction like the sphere/shell problem.)
BTW, Gary. Found any real physics examples yet of a heated object making its heat source even warmer by radiation?
Well, let’s see who breaks what laws.
Assuming surface area of sphere is approximately the same as the inner and outer surface areas of the shell at 1 square meter, and assuming at radiative equilibrium the sphere radiates power J = 400 watts to the shell, then from Problem 1023’s solution the shell radiates J1 = 200 watts outward and J1 = 200 watts inward toward the sphere. So far so good.
Now science says the sphere must be getting 200 watts from somewhere (e.g. internal radioactive decay) to maintain radiative equilibrium. As I recall, Kristian says its internal source must be generating 400 watts!
If “Q” is the internal power supplied to the sphere, then science says
Q = 200 = J/2 = J1
Kristian says
Q = 400 = J = 2*J1
Kristian is perfectly happy to put 400 W into the system and get 200 W out. Good-bye conservation of energy! 🙂
Joel said:
“In other words, you don’t particularly like the actual laws of physics, so you are just going to make up your own”
That’s exactly how I see the AGW position since it ignores much of the physics of non radiative energy transfers in favour of an overly radiative solution.
The problem of atmospheric energy content must be non radiative because the atmosphere obstructs radiative energy flows in order to achieve its effect.
Non radiative processes being slower than radiative processes there must be a build up of energy within the system and that energy build up must be proportionate to the relative speeds of the two types of process.
Since ToA energy balance is maintained over time and since the surface to atmosphere energy exchange is in balance right at the surface, logic tells us that there is no net upward or downward radiative energy flow between surface and ToA other than the background solar throughput.
The temperature profile from surface to ToA is determined by the decline in pressure with height and not by radiative fluxes.
If there is no net DWIR or UWIR then radiative characteristics cannot be having any effect on the speed of energy throughput after the negative system response has been taken into account.
Just an observation. I think polystyrene, while being a very poor conductor of heat is a more transparent to IR than the other film. I maybe wrong about this, but if I’m right what does that do to the experiment?
MikeA
That’s a thought!!!!
The Radiative Effectiveness of Plastic Films For Greenhouses:
http://journals.ametsoc.org/doi/pdf/10.1175/1520-0450%281963%29002%3C0793%3ATREOPF%3E2.0.CO%3B2
My box was mainly polyethylene. I have now put polished Aluminium Foil on inside of chamberto reflect IR.
TFP
Its futile to look for the Greenhouse Effect in a shoebox sized enclosure.
R W Woods results of his famous experiment have never been falsified.
Here is an experiment staged over a number of years to find out the influence of radiative blocking plastic on greenhouse temperatures.
This also is an interesting paper especially as it comes from a source with no “spin” on the AGW debate.
It gives massive support for the conclusions of the famous Woods experiment.
Basically the project was to find if it made any sense to add Infra Red absorbers to polyethylene plastic for use in agricultural plastic greenhouses.
Polyethylene is IR transparent like the Rocksalt used in Woods Experiment.
The addition of IR absorbers to the plastic made it equivalent to “glass”
The results of the study show that( Page2 )
…”IR blocking films may occasionally raise night temperatures” (by less than 1.5C) “the trend does not seem to be consistent over time”
Some evenings they would also find an anti- greenhouse effect.
That’s when the temperature inside the greenhouse was less than the ambient temperature outside.
http://www.hort.cornell.edu/hightunnel/about/research/general/penn_state_plastic_study.pdf
“The influence of mankind on climate is trivially true and numerically insignificant.” Richard Lindzen
Gerhard Gerlich and Ralf D. Tscheuschner put it another way
‘the radiative effects of CO2 while significant at furnace temperatures are insignificant at atmospheric temperatures.
The only credible version of the greenhouse effect is the one Nullius in Verba advocates.
The ‘greenhouse’ in this version is several kilometers high.
Bryan
I am not trying to prove the absolute values of GHG effects.
All I am aiming to show is that a cool object will cause an internally heated hotter object to get hotter. If only a few hundredths of a °C increase in temperature can be obtained my case is proven and cool can cause a heated object to get hotter. This would then slay the slayers theories.
I beliueve that I already have shown the steel greenhouse effect to be valid (not by showing an exact match in theoretical temperature gains, but by showing that the effect is there).
WWithout a planet sized lab Roy and my experiments cannot hope to prove the GHG effect to the nearest 10th of a degree they are not meant to! But if a cooler object can slow the cooling of a hotter oject, or even allow a constant power input object to get warmer then the slayers theories are blown out of the water!.
TFP says
“But if a cooler object can slow the cooling of a hotter oject, or even allow a constant power input object to get warmer”
Can you give an example of a spontaneously occurring constant power input?
That is one which will step up its output to overcome an increasing impedance.
Bryan
Can you give an example of a spontaneously occurring constant power input?
———–
Why would you need to step up the power. All that is required is a constant power into the hot plate and a cold source adding exra quanta.
This effectively increases the power and gives a warmer temperature
Do you agree with my previous statements.
Slayers are slayed if a cooler object causes an increase in temperature of an object with fixed power input or a reduced cooling rate of an object with no additional power input?
i.e. a cooler object transfers energy to a warmer object which then thermalises the energy.
If not what are your objections?
TFP
Do you mean constant power of output from source.
Or constant power of input to sink?
In other words the same number of joules per second delivered to the sink irrespective of the temperature of the sink?
The hot object is heated by a constant power (V^2/R) this will not change with hot object temperature it is just V^2/R
R is resistance – Unchanging
V is voltage – unchanging
Total power into hot object is V^2/R + quanta from any object above 0K.
The cool object will be emitting quanta in all directions. Some of these will be intercepted by the hot object.
These intercepted quanta will add to the joules absorbed by the hot object per second
TFP
If the temperature of the source rises then you are wrong to say
“R is resistance – Unchanging”
The resistance will rise.
So the power will not be constant.
This result is quite typical and anyone who specifies a constant power requirement is really asking for a specialised piece if electrical engineering equipment which will do this job after a fashion within certain limits.
What happens to a warmer hollow sphere if a colder object is placed inside?
By your reasoning it should get even warmer but common sense or a calculation shows it gets colder.
A hot object will heat a colder object never the other way round.
If a hot object with a continuing power supply has its heat loss mechanisms restricted then it will often rise in temperature but the heat is coming from the electrical energy of the supply.
Switch the power off and the cold object will never raise or even halt the temperature of the cooling hot object
The colder object is merely acting as insulation.
The same result would be obtained if convection or conduction were restricted.
So there is no special status for the radiative insulation effect.
Bryan says:
May 21, 2013 at 3:49 PM
TFP
If the temperature of the source rises then you are wrong to say
“R is resistance – Unchanging”
The resistance will rise.
So the power will not be constant.
—————-
Bryan I have been an electronics design engineer for decades!
Resistors have a temperature coefficient
– most small resistors <£0.03 can be +-15ppm (resistance increases/decreases [specs don't say which] by 0.0015%/°C)
specialist resistors can be much better and have a predictable temp coefficient curve.
However, your statement about resistance is PROVEN wrong
———–
Bryan
If a hot object with a continuing power supply has its heat loss mechanisms restricted then it will often rise in temperature but the heat is coming from the electrical energy of the supply.
———–
We have already proved that the electrical power in is constant so this statement is WRONG.
Yes the heat is coming from the electrical power but this is constant. Resricting heat loss will raise the object temperature. Restrict it 100% including IR and the object will reach "unlimited" temperatures.
keep the rate of loss through conduction and convection constant and zero and you are only left with IR.
Keeping conduction and convection zero is just about impossible in lab experiments. Hence DrSpecncer and my experiments will not show the full back radiation effect.
A possibility would be to adjust the electrical power input to maintain a constant temperature (i.e. conduction and convection are constant but non zero) however. the time constant of elect in to heat out is long making the experiment almost impossible.
————
Bryan
The colder object is merely acting as insulation.
———-
This is a possibility. However in my experiment the hot object is in a thermally insulated container and the warm object is about 7cm from the outside of the container – not a good place to put a piece of insulation. It is also isolated from the hot object for convection and conduction.
It still shows warming
It staggers me that you claim to be an electrical engineer yet you are unaware of the fact that most metals have a strong resistance dependency on temperature.
http://www.electrical4u.com/resistance-variation-with-temperature/
If you look back to my original posts you will see that I said you can design special circuits that will give almost constant power after a fashion within certain limits.
Machines can be constructed that ‘appear’ to violate the second law such as refrigerators.
However any good physics textbook will explain that this ‘appearance’ is wrong
Classical Thermodynamics is about spontaneous thermal behavior.
Constant power input does not spontaneously occur.
Bryan says: May 23, 2013 at 2:14 AM
It staggers me that you claim to be an electrical
—–
No I said ELECTRONIC!!
—–
engineer yet you are unaware of the fact that most metals have a strong resistance dependency on temperature.
…
If you look back to my original posts you will see that I said you can design special circuits that will give almost constant power after a fashion within certain limits.
———
Bryan
What on earth are you rambling about.
I thought this was talk about the design of an experiment.
If you drive a car I would expect that your life relies on some of the products I have helped design – so I hope your concerns about my ability is not Fact!!!!!!!
Constant power is easy to CONSTRUCT
1 off 2ppm resistor 1 off constant voltage source = constant power.
Nothing specialised -simple.
However:
—-
Bryan
Constant power input does not spontaneously occur.
—-
The heat emerging from the earths core is “constant over a few years.
The heat produced by radioactive decay can be constant for many days.
The heat produced by a human body at rest will be “constant” over a few minutes
The heat produced in an explosion will be constant over a yocto second!!
You must define “constant” in terms of time and stability if you wish to continue this stupid discussion.
HOWEVER it would be better to criticise the design of experiment Dr Spencer and I have done/proposed. If you can find no sensible criticism, will you then accept the results?
TFP says
“You must define “constant” in terms of time and stability if you wish to continue this stupid discussion.”
I have very little inclination to continue this particularly stupid discussion.
So I now understand that you think its all right for an electronic engineer to know very little about the fact that
most metals have a strong resistance dependency on temperature.
You also fail to read properly my posts where I asked you to define which constant power YOU were referring to!!!!
Is it constant power output of source or constant power input to sink?
http://www.maximintegrated.com/app-notes/index.mvp/id/4470
This discussion reminds me of your last extended series of posts where you were claiming that the pyrgeometer gave a direct reading of back radiation.
You must read carefully the posts of others if you hope to make some progress
TFP
“Bryan I have been an electronics design engineer for decades!
Resistors have a temperature coefficient
– most small resistors <£0.03 can be +-15ppm (resistance increases/decreases [specs don't say which] by 0.0015%/°C)
specialist resistors can be much better and have a predictable temp coefficient curve."
This is complete nonsense.
Every schoolboy knows that if you heat a metal its resistance rises.
So if the supply voltage stays the same and the resistance rises with temperature then the current decreases and output power decreases.
TFP then draws the wrong conclusion
"However, your statement about resistance is PROVEN wrong"
Go back to school
some metals have resistances that are stable:
http://www.isabellenhuette.de/en/precision-and-power-resistors/products/
20ppm/K
Resistors at £15 each and you have 0.2ppm
http://www.vishaypg.com/docs/63106/vfcpseri.pdf
Why are you quibbling?
Lets assume you use an unstable resistor. What stopos you monitoring voltage and current and adjusting voltage to maintain the same power input VxI.
Please bring up a sensible criticism!
As a slight aside, you can buy a thermopile for US $15 here:
http://www.sci-supply.com/closeup.asp?cid=124&pid=481&offset=0
Then anyone can build their own cheap, uncalibrated pyrgeometer/IR detector.
Hi Tim,
uhmm… Not sure it’s a real thermopile (intended as the ones made of metal junctions), it looks more like a silicon based Peltier cell.
Here is one from HK at cheaper price:
http://www.ebay.com/itm/136-8W-TEC1-12709T125-Thermoelectric-Cooler-Peltier-12V-/221041861016?pt=LH_DefaultDomain_0&hash=item33771f2198
I have some 110W/12V that I bought two or three years ago for the thermal pumping of some power devices.
Being almost a reversible thermal machine, they generate some mV when one of their sides is exposed to a warmer object.
And… Yes! They generate some mV also when one of their sides is exposed to a cooler object too 😉
To use them as a pyrgeometer/IR detector one should keep the other side at constant temperature, otherwise one should track the other side temperature and correct the measurement for that thermal reference.
Joel Shore says:
May 18, 2013 at 1:37 PM
“It is not inhibited. Your whole point is that the 390 W/m^2 go out no matter what. (Just as the 240 W/m^2 would freely escape the surface as radiation before you put GHGs in the atmosphere (same albedo). Purely a function of temperature.)”
No…It is not 390 W/m^2 no matter what. If there were less GHGs in the atmosphere, then the surface would be cooler because it wouldn’t need to radiate 390 W/m^2 in order to have 240 W/m^2 escape to space. In fact, if the atmosphere didn’t absorb any radiation, it would only have to radiate 240 W/m^2 and would hence have a lower temperature accordingly.
“Well, then. If the absorbed heat from the Sun is always free to escape the surface again unhindered as thermal radiation, purely as a function of the resulting temperature, then how is the surface temperature radiatively raised? If not by the Sun (assumed constant), then by what?”
The temperature is raised because the temperature is determined by the condition that the Earth has to radiate back into space the same amount of radiation as it receives from the sun. This thus depends not only on how much radiation it receives from the sun but how easily (i.e., what surface temperature it has to maintain) to radiate 240 W/m^2 back out onto space.
“OK. So if the surface temperature rises when this energy is added and all else (Sun/surface) is equal, then tell me how this energy transfer does not constitute a transfer of HEAT from cooler atmosphere to warmer surface?! Exactly what you said the atmosphere didn’t do.”
Because the net macroscopic flow of energy is still from the Earth to the atmosphere. If I get paid $1000 per month and I give my landlord $500 of it and then he lowers my rent and only charges me $400 per month, then do we say that the net flow of money is now from my landlord to me?
“The troposphere is taking heat away from the surface … but much less efficiently when the atmosphere is heavy (massive) than when it is light (less massive).” The atmosphere restricts free convective and evaporative heat loss from the surface, its main heat loss mechanisms, by being massive and pressing down on the surface.
Yes, one of the most sophistic posts so far on this thread!
I see it’s only an excerpt. Read the whole thing here:
http://www.drroyspencer.com/2013/05/a-simple-experiment-to-show-how-cool-objects-can-keep-warm-objects-warmer-still/#comment-80203
Quite rich!
Kristian,
And yet, it seems that most people here, including many like Roy Spencer and Salvatore, who are AGW skeptics agree with what I am saying. That brings up two possibilities:
(1) Kristian is so much more brilliant than the rest of us that he has been able to arrive at a better understanding of the GHE, the Second Law of Thermodynamics, and the relationship between the two than people like myself who have actually studied…for many years…the underlying statistical physics that gives rise to these thermodynamics principles.
(2) Kristian is wrong.
One wonders which possibility is more likely.
That is part of what Joel Shore had to say a few days back Stephen which says it all.
Why you can’t follow this or accept this way of thinking baffles me.
Salvatore,
I respect your intellectual integrity since I know from our direct communications some time ago that you can change your position when the evidence merits it.
So please consider the following which is part of an exchange of views at tallbloke’s blog:
“One can regard the atmosphere itself (independently of solar throughput) as having a zero radiative flux. In other words no net upward IR and no net downward IR.
One is driven to that conclusion by noting that there is radiative balance at ToA between atmosphere and space and also radiative balance at the bottom of the atmosphere between surface and atmosphere.
So, just using any numbers as an example if 240 comes in at ToA then 240 goes out at ToA and if 150 leaves from surface to atmosphere and 150 leaves from atmosphere to surface there is no net radiative flux within an atmosphere other than the basic throughput of solar energy.
If the only net flux that can exist within an atmosphere is from solar energy passing through then GHGs cannot create a different net flux without a compensating circulation adjustment that cancels out their effect.
Now I’m sure that is the reality but demonstrating it is quite a problem.”
Let me make my position clear.
I have no personal, professional or ideological interest in the climate debate other than trying to get it right.
It is obvious to me as a weather and climate enthusiast for over 60 years that the consensus view is not right.
If I get trashed on the blogs it matters not. My life goes on.
Everything I say is a simple search for truth motivated by nothing more than a deep interest in weather and climate instilled into me at an early age and pursued intensively ever since.
I was in this game long before the AGW proponents.
Stephen we agree on much, other then the GHG effect, which I say Dr. Spencer has shown to be real through all the evidence he has posted over the recent weeks.
IF YOU READ THE POST SURFACE RADIATION BUDGET WHERE IS THE PROOF, posted May 13 ,that alone to me shows very conclusive evidence that a GHG effect is real and is needed in order to account for why the climate of the earth is what it is, and how it might change.
In the absence of this GHG effect, I can’t make the argument for cooler tmeperatures going forward, or account for why the atmospheric temp. profile is what it is,or why even the weather is the way it is.
I know you think you have an alternative but I think enlight of ALL the evidence Dr. Spencer has presented plus data itself that the GHG effect is for real, and has to be taken into account if one wants to get an understanding of earth’s climatic system.
Stephen I am quite sure after reading the many post and evaluating as much as I can understand that the temperature of the earth without no GHG would be around 33 c colder then it is currently, given the most recent current situation.
I do believe however that this 33c temp. difference varies over periods of time , being greater or less.
I think it depends on the relative strength of the GHG effect which I think is a result of the total energy in the climate system of the earth ,which in turn is regulated by solar conditions over the long haul.
I think the GHG effect is real but how effective or not it is, is a consequence of the current climate situation that is taking place over the earth from ocean temperatures, to the amoutns of IR the earth emits and the wavelengthsit emits at most frequently,, to the degree of relative saturation the GHG’S are for certain IR wavelengths the earth does emit.
Well, Salvatore, I made it clear up thread that the greenhouse effect certainly does exist.
However I think it is caused by atmospheric mass and not radiative characteristics of constituent molecules.
Roy made a comment somewhere that I thought indicated that he agreed that atmospheric mass is a factor.
Well then, I would like Roy to specify how much of that ‘extra’ 33C he thinks is attributable to mass and how much to GHGs.
Previously I suggested that the whole 33C is down to mass and that any attempt by GHGs to contribute to that is offset by circulation changes.
Roy asked certain questions which I think I answered adequately.
Roy went quiet.
Roy seems to think that an atmosphere devoid of GHGs would have no convection. I explained why it would.
Roy has not commented.
Over at tallbloke’s I have expressed my opinion this:
“One can regard the atmosphere itself (independently of solar throughput) as having a zero radiative flux. In other words no net upward IR and no net downward IR.
One is driven to that conclusion by noting that there is radiative balance at ToA between atmosphere and space and also radiative balance at the bottom of the atmosphere between surface and atmosphere.
So, just using any numbers as an example if 240 comes in at ToA then 240 goes out at ToA and if 150 leaves from surface to atmosphere and 150 leaves from atmosphere to surface there is no net flux within an atmosphere other than the basic throughput of solar energy.
If the only net flux that can exist within an atmosphere is from solar energy passing through then GHGs cannot create a different net flux without a compensating circulation adjustment that cancels out their effect.
Now I’m sure that is the reality but demonstrating it is quite a problem.”
I would like an answer.
“also radiative balance at the bottom of the atmosphere between surface and atmosphere.”
Why? I see no reason why there has to be radiative balance at the bottom of the atmosphere. There needs to be energy balance, but there are plenty of non-radiative ways that energy can be transferred between the surface and atmosphere.
There needs to be radiative balance at the TOA (or at least the system will always been driven toward that) because that is the only significant type of energy transfer that can occur between the Earth and space.
You say things like “the AGW position since it ignores much of the physics of non radiative energy transfers in favour of an overly radiative solution”. But, the actual fact of the matter is that the AGW position understands when one needs to consider non-radiative transfers and when one needs to consider only radiative transfers. And, furthermore, it considers them correctly rather than just making up physics to suit one’s prejudices.
Furthermore, whether or not there needs to be radiative balance at these two places is irrelevant to whether there is a radiative greenhouse effect or not. In a simple shell model (i.e., Willis’s “steel greenhouse”), there is radiative balance at all points but there is also clearly a radiative greenhouse effect. See, that is the advantage of having mathematical models using known equations of physics: You can actually test ideas rather than operating in the sort of epistomological nonsense-land that reigns supreme over at Tallbloke’s.
Joel,
You have highlighted by reference to a simple shell model exactly where it seems to me that the radiative theory as applied to the GHE goes pear shaped. I have studied literature that you and Nullius directed me to and there seems to me to be a obvious error that supports Stephen’s analysis. In the theory and calculations that support back radiation in the instances of furnaces and the like; these all assume a single reflecting surface as with the simple shell model. In reality the atmosphere does not present anything like a single reflecting surface. Rather than having a single reflecting surface radiating back to the Earths surface it has no effective surface at all; either at the bottom, or at the top! It is actually a multitude of layers each reflecting back to the previous; and significantly each layer is slightly less dense than the previous; a characteristic which in itself will encourage flow from dense to less dense. Think of it as circles of pins (representing IR absorbing molecules) around a central point with each subsequent circle of pins having pins slightly further apart as you move away from the centre. A ball (representing energy) will find it easier to move away from the centre to the outside and near impossible to get from the outside to the centre. This is a far better analogy with the reality of the atmosphere. The impact on the Earths surface will only be from the layer in contact with the surface and then will gradually reduce continually from there. The Earths atmosphere shouldn’t be considered as a shell but more of a continuation of the surface that gets less and less dense; encouraging the IR to flow away to the point in the atmosphere where it can escape; which once again is not going to be at the TOA because it could escape anywhere from the surface up. It just depends how many pins it happens to hit on the way through!
Iansview,
Of course the shell model is an approximation! What you describe is not an error…The shell model is just a model to allow one to get a qualitative understanding of what is going on. To read about the equations that are actually used to quantitatively study radiation transfer in the atmosphere, go here: http://scienceofdoom.com/2011/02/07/understanding-atmospheric-radiation-and-the-%E2%80%9Cgreenhouse%E2%80%9D-effect-%E2%80%93-part-six-the-equations/
And, no, the fact that we sometimes consider simpler qualitative models to get a picture of what is going on rather than doing the full quantitative calculation has nothing to do with Stephen Wilde’s manifestly incorrect nonsense being supported in any way.
(Also, as a correction to what you have said, the shell model does not assume a reflecting surface…In fact, it generally assumes a perfectly absorbing, i.e., blackbody surface… although it can be extended to assume a partially transparent surface or partially reflecting surface or multiple surfaces of various types.)
You have to go back to what Joel Shore said which I posted about 2 hrs ago.
i AM WITH THAT WHICH IS RADIATIVE PROCESSES
Sorry Salvatore, but the post you refer to (11.59am) does not contain any comments from me nor does it address the points I have made.
If the surface receives 240 from the sun then the atmosphere radiates 240 to space, 150 to the surface and the atmosphere then receives 150 back from the surface which then achieves 390.
Variations around those numbers from internal system variability are a given.
The questions are:
i)) How much of that 150 back to the surface is from mass and how much from GHGs.
ii) Given that GHGs do not add to the amount of energy coming from the sun they can only redistribute existing energy so do they really add to surface temperature rather than simply provoking circulation changes ?
iii) Is that 150 being returned to the surface a direct radiative energy flow or an indirect radiative energy flow resulting from the reconversion of PE to KE from descending air ?
iv) If the ToA radiative exchange is set at incoming (say 240) and surface to atmosphere radiative exchange is also balanced (at say 150) then how can there be any net DWIR or UWIR in the atmosphere ?
v) If there is no net upward or downward radiative exchange in the atmosphere how could GHGs change that without upsetting ToA radiative balance so as to cause the atmosphere to be lost ?
My suggestion is that between the lowest molecules of the atmosphere which radiate to the surface at 150 and the highest molecules of the atmosphere that radiate to space at 240 everything is non radiative, i.e. conduction and convection but admittedly with complications from the phase changes of water in the troposphere, direct solar shortwave heating of ozone in the stratosphere and perhaps other processes higher up of which we know little.
However whatever happens between that 150 to the surface and 240 to space MUST be dealt with by circulation changes because energy out at ToA can never exceed or fall short of energy in at ToA for any length of time if an atmosphere is to be retained
Mr. Stephen Wilde.
Suppose TOA radiate 240 W/m2 for the space. It will radiate 240 w/m2 to the surface of the planet as well. TOA should receive 480 w/m2 by radiation, conduction or convection.
If the surface receives 240 from the sun then the atmosphere radiates 240 to space, 150 to the surface and the atmosphere then receives 150 back from the surface which then achieves 390.
A body at a given temperature — here, the atmosphere — does not radiate different amounts in different directions. It radiates the same in all directions.
But the atmosphere is not “at a given temperature”. The top is much cooler than the bottom. Hence the top of the atmosphere radiates less to space than the bottom of the atmosphere radiates to the surface.
There is no such thing as TOA really is there? IR can escape at any level from the atmosphere purely dependent on whether there’s something in its way. See my response to Joel above. I explain there why the IR emitted from the surface is not reflected in the fashion thought and how the simple shell model is wrongly applied.
It is not “wrongly applied”. It is an approximate model that allows us to get a simple qualitative picture of what is going on. (See my response here for more detail: http://www.drroyspencer.com/2013/05/a-simple-experiment-to-show-how-cool-objects-can-keep-warm-objects-warmer-still/#comment-80440
What you are making is a common error that people make when scientists show them simple models that illustrate the behavior: They think that these simple models are “as good as it gets”. The reality is that the actual models used to do the full radiative transfer calculations are much more complicated, but it is not very enlightening to throw 10000 lines of computer code at you and say that this is the model. That is why scientists tend to develop models at very degrees of complexity.
“…at very degrees of complexity” should be “…at various degrees of complexity”
Tim Folkerts says:
But the atmosphere is not “at a given temperature”. The top is much cooler than the bottom.
But Stephen Wilde is treating it as a single layer. That’s the point. A proper analysis divides the atmosphere up into an infinite number of infinitesimally thin slabs; and each layer radiates the same amount of energy downward as upward.
I’m treating it as an infinite number of thin slabs as Iansview realised.
The topmost layer lets 240 out to space whilst the bottom most layer exchanges 150 with the surface.
That says nothing about what happens in between which is the regime of non radiative processes which lead to radiative outcomes that vary considerably in three dimensions.
Stephen Wilde:
Our atmosphere should be divided into N layers with absorption of 100% or 50% attenuation of the infrared rays. Each layer re-radiates this energy up and down also besides receiving power movements comvectivos.
When radiates 50% up and 50% down as each horizontal layer infinitesimal must be considered as an emitter Labertiano otherwise not find any result.
We need take a “attenuation profile”of the atmosfere by radio-sounding. It’s a work for Dr. John Christy friend of Dr. Roy.
A Google search on CO2 infrared experiments comes up with some examples, including a good one on You Tube.
Regarding all the debate about colder objects reflecting IR back to hotter ones, it occurs to me that while the atmosphere as a whole may be cooler than the surface, an individual CO2 molecule, having absorbed a photon of IR, becomes in a sense hotter than the molecules around it, right?
Hops
Do the math — compare the kinetic energy of a CO2 molecule to its IR molecular energy levels.
JOEL SHORE QUESTIONS
GHG EFFECT IS PRESENT THAT IS A GIVEN.
QUESTIONS: Do you think the effectivenes of the GHG effect changes over time or is a constant?
If you think it changes, how and why does it change?
I say the answer to the first question is the GHG EFFECT changes over time.
I say the answer to the second question is the GHG effect(how effective it is) is related to the total energy coming into and leaving the earth climatic system. Anotherwords how effective the GHG effect is in increasing the temp. of the earth higher then would be otherwise(without any greenhouse gases), depends on how much energy is in the earth climatic system, for the greenhouse gases to work with and influence.
Do you think this is proper reasoning,or not and why? Thanks
Iansview, how do you account for the temp. profile of the stratosphere given you don’t think the GHG effect is valid?
How do you account for what high concentrations of SO2 can do to the stratopshere and the lower troposphere if you don’t believe in a GHG effect?
How do you account for small temp. differences between night and day in the tropics where water vapor concentrations are high versus large temp. differences over deserts between night and day time temperatures where water vapor concentrations are low ,if you don’t believe in a GHG effect?
How do you reconcile the temp. profile of the atmosphere as a whole if you don’t believe in a GHG effect?
or at least the way Roy, and others are trying to present how the GHG EFFECT works in their opinions.? Which is the
GHG EFFECT SERVES TO WARM THE LOWER ATM. AND COOL THE UPPER ATM causing the atm. to be unstable and promoting convection and weather.
I can’t come up with an alternative for any of these items I have presented.
As a suggestion, I know it’s not home-ready stuff, but an even better test would be in a vacuum with some calibrated thermocouples. You would have to use a cartridge heater (or equivalent) and some thyristors to control the heat being put into the “hot” and “ambient” plates. Bring them to temperature and then turn off the heaters and watch it play out.
I would be willing to run this experiment at work. However I’m afraid our vacuum chamber is in constant use at the moment and it may be some time before it is available again.
My shocking prediction? The hot plate on the ambient side will cool more slowly. Either that or heat will quantumly tunnel from the ambient plate to the bottom of the ocean where it will wait until the next UN summit.
If you have the facilities, wouldn’t it be better to do a steady state experiment, i.e. with continuous “external” heating of the “warm” plate?
http://www.drroyspencer.com/2010/07/yes-virginia-cooler-objects-can-make-warmer-objects-even-warmer-still/
I don’t expect an experiment done by a “warmist” to convince any “Slayers” (they’d have to do the test themselves and even then probably wouldn’t believe it), but it could be a useful educational tool.
STEPHEN
i. all from GHG
ii. the GHG add to the temp. of the earth by not allowing IR radiation to escape directly to space.
iii. the ghg distribute the energy given off by the surface and redirect the energy given off by the surface of the earth back to the surface hence higher temp. then what would be otherwise
iv there is a radiative ghg balance which ties into the amounts of energy in the earth /climate system
v the atm.through ghg ‘s directs IR radiation downward in the lower atm. and upwards in the higher atm., hence the ghg effect is to warm the lower atm and cool the upper atm.
All,
This is just going in circles (doesn’t it always?) but I put it to you that you are not seeing the forest for the trees.
There is one question that BOTH sides need to answer before all the theorising can begin. That is:
“What portion of the Greenhouse Effect (GHE) is contributed by CO2?”
Stephen Wilde has asked this question (as have I) and has received no quantitative response. (Or, if there has been a response, I apologise for missing it)
Until this question can be answered to a reasonable accuracy and, more importantly, be backed up with real-world evidence, the debate about radiative forcing is mute. You can all push numbers like 240 and units like W/m^2 around all day but these are effectively meaningless until there is some factual basis for the discussion.
Follow-on questions are:
“How much of the ‘enhanced GHE’ since 1850 (IPCC date) is contributed to by CO2?.”
And:
“What was the contribution of CO2 to the GHE in 1850?”
I do hope you can see the importance of these questions. Everything in the cAGW leads from this. Papers which assume the veracity of the radiative GHE are based on an assumption. Papers which conclude a climate sensitivity are based on an assumption.
Provide support for the original theory and the debate has meaning. Otherwise, it is all hand-waving.
Stick to the facts (or at least as close to facts as it gets in the cAGW debate):
The alleged GHE today is 33 deg C.
The measured increase in GHE (enhanced) since 1850 is 0.8C (HadCRUt).
Therefore, the GHE in 1850 was 32.2C (provide your own figures if you disagree).
Since 1850, CO2 has increased by appx 40%
Since 1850, CH4 has increased by appx 150%
Since 1850 water vapour concentration has stayed relatively steady.
Now, if the two main non-condensing GHGs have increased so significantly, why has there not been a correspondingly-significant increase in the GHE? Or, if 280ppm CO2 can be so significant pre-1850, how come 398ppm hasn’t evidentially made a difference?
A few points before you jump in…
The warming between 1910 and 1945 was exactly the same as the warming between 1975 and 1998, but with virtually no increase in CO2. What caused this warming?
There has been no accelerative rise in global temperature since 1998, and it can be reasonably argued that there has been no rise at all. Why not?
‘Thermal Inertia Lag’ has no evidential support, apart from an apparent five-year lag in OHC increase.
There is absolutely no evidence to support the conjecture that increased CO2 (and other nGHGs) has caused the rise in OHC (as measured over a relatively short term).
There is absolutely no evidence to support the idea of ‘positive feedbacks’ leading to significant GHE increase.
There is evidence to support the notion that natural factors can affect the GHE.
To conclude:
Answer the simple questions and provide supporting real-world evidence before you start arguing that the majority of the GHE is due to radiative factors. Answers from models are irrelevant.
I’m not saying that either side (radiative GHE or ‘Slayers’) is 100% correct, but this is a fair place to revisit the original theory. No-one doubts that nGHGs can emit and absorb radiation. The point is do they have any significance in the real-world atmosphere? If you think so, can you provide proper evidence?
Regards,
“Since 1850 water vapour concentration has stayed relatively steady” – Incorrect.
Older data is a challenge, but satellite measures of at least the last 15 years show clear increases in total water vapor/specific humidity (Trenberth et al 2005, Trends and variability in column-integrated atmospheric water vapor), while relative humidity has not significantly changed 1975-2005 (Dai 2006, Recent Climatology, Variability, and Trends in Global Surface Humidity).
And by the Clausius-Claperyron relation as temperature rises with fixed relative humidity, total water vapor increases as well – by ~4% over the last 40 years.
Note that if temperatures had risen the observed 0.8C without increases in specific humidity, relative humidity would have dropped significantly with corresponding effects on precipitation (i.e., a lot less of it), which has not happened – relative humidity is pretty stable. Hence that first-pass feedback of increased total water vapor is in operation.
As to the increased greenhouse effect, that is directly observed in outgoing IR spectra (Chen et al 2007, Spectral signatures of climate change in the Earth’s infrared spectrum between 1970 and 2006) – decreases in outgoing IR right where theory predicts it for increased CO2, CH4, and H20. Less IR exiting the top of the atmosphere at any particular temperature, thus energy imbalance, thus warming until that imbalance is neutralized at a higher climate temperature.
From that paper and measured changes in GHGs, “…the greenhouse forcing of the Earth has been observed to change in response to these concentration changes.”
During the period in question there were less clouds and more energy entering the oceans so the oceans held on to it longer and OLR may well have dropped a little but that wasn’t the greenhouse effect.
The process now seems to be in reverse despite still rising CO2.
It was simply solar induced variations in albedo and a time lag introduced by the oceans.
No one disagrees that the greenhouse effect varies around the mean due to internal system variations.
That was one such example.
However those internal system variations result in a negative system response from circulation changes, not a positive one.
Arfur Bryant.
In 1880-1890 the planet was cooling -0.4 degrees. Germany developed its agriculture importing Chile nitrate. 1910-1912 German cargo ships sink blocking the import of nitrate. Haber & Bosch develops the manufacture of ammonia directly from the atmosphere. 1914 explodes the great world war. 1920 expionagem American industrial proscesso can copy the manufacturing of ammonia and begins to spread around the world, with fertilization-derived amönia.O planet begins to warm. 1945 explodes 2a War.
Ammonium is diverted from agriculture to manufacturing explosives. The planet back to cool. The sequence from here all know.
Explanation ….. ammonium solubilizes the ground clay in the soil profile decendo blocks the pores and micropores thus hindering the water storage. We do not have sufficient water for evaporation and convective motion by a moist adiabatic. Alters the distribution of energy in the profile of the atmosphere.
D’Avila Tarcisio
Thanks for that fascinating idea. Do you have any evidence to support the idea?
And thanks for making my point that the 1910-1945 warming had nothing to do with CO2… 🙂
KR,
Firstly, I notice yo haven’t even addressed my prime question, upon which all discussion should proceed.
[“Older data is a challenge, but satellite measures of at least the last 15 years show clear increases in total water vapor/specific humidity…”]
Wrong.
http://www.climate4you.com/images/TotalColumnWaterVapourDifferentAltitudesObservationsSince1983.gif
That shows water vapour has remained constant (or actually slightly reduced) since 1983.
[“Note that if temperatures had risen the observed 0.8C without increases in specific humidity, relative humidity would have dropped significantly with corresponding effects on precipitation (i.e., a lot less of it), which has not happened – relative humidity is pretty stable.”]
Relative humidity has remained steady near the surface but not in the upper tropopause:
http://www.climate4you.com/images/NOAA%20ESRL%20AtmospericRelativeHumidity%20GlobalMonthlyTempSince1948%20With37monthRunningAverage.gif
Please note these are official data.
And finally…
[“From that paper and measured changes in GHGs, “…the greenhouse forcing of the Earth has been observed to change in response to these concentration changes.””]
It is really sweet of you to try to condense the entire cAGW theory to a period of 35 years!
If the nGHGs were responsible for that warming, what caused the earlier warming and why has the temperature flattened later?
You can’t eat your cake and have it.
I suggest you read the Trenberth et al paper I referred you to, and note their cautions about data quality. I will note that I have personal cautions about the Climate4You data, based on his (mis)conflations of GISP proxies and global temperatures.
WRT the Chen et al data, that is clear experimental evidence for reductions in IR to space, at specific CO2 and water vapor absorption frequencies, and reduced emissivity is the direct connection to energy imbalance and global warming. Do you consider the Stefan-Boltzmann law a ‘model’?
As to the mid-century warming, please do not make the mistake of assuming that anthropogenic forcings are the only influence on temperatures. Midcentury warming involved high insolation (declining for the last 40 years) and very few volcanic events (far more in the latter half of the century) – http://data.giss.nasa.gov/modelforce/ has one of the more respected data sets for net forcings over that period.
Also note that the slopes are not equivalent in all data sets – the HadCRUT data in particular underestimate polar regions which exhibit the most warming (assigning global average values to those regions rather than near-polar values). GISTEMP, based on correlation of temperatures over distance, shows a late-century rate of warming some 60% higher than mid-century over those time frames.
And as to total forcings (from a zero-GHG atmosphere), which appears to be your earlier question? I believe CO2 accounts for 34-40% or so (can’t find the appropriate reference at the moment), or ~50-6 W/m^2 of total forcings, much of the rest in water vapor. How is that relevant to climate change? The question there is how forcings and temperatures have changed, and how those affect the climate civilization developed in. Not Gedankenexperiments about zero-GHG environs.
—
WRT to your questions on GHGs versus temperature change – 0.8C is quite consistent with what we ‘should have seen’ from the IPCC numbers (http://tinyurl.com/bu2w5a7), including climate sensitivity estimates. You cannot ignore thermal inertia, or for that matter aerosol forcings, in calculating an expected response.
Consider things as simply as possible – but not too simple, or you will make errors.
KR
[“And as to total forcings (from a zero-GHG atmosphere), which appears to be your earlier question? I believe CO2 accounts for 34-40% or so (can’t find the appropriate reference at the moment), or ~50-6 W/m^2 of total forcings, much of the rest in water vapor. How is that relevant to climate change?”]
34-40%! Are you serious? My question was quite clear. What is the contribution of CO2 to the ‘GHE’. If you are seriously suggesting that CO2 is responsible for 34-40% then you are living in la-la land.
I have read Trenberth, and my question still stands. What you, Trenberth and everyone else who still clings to the radiative forcing from CO2 = AGW” theory seems to ignore is that there WAS a ‘GHE’ (or Atmosphere Effect) before 1850. That ‘GHE’ was only 0.8C less than ti is today but we have seen a 40% increase in CO2 and a 150% increase in Methane but we have only seen a 0.8C rise in temperature but we don’t know how much of that 0.8C rise is due to CO2!
[“WRT to your questions on GHGs versus temperature change – 0.8C is quite consistent with what we ‘should have seen’ from the IPCC numbers (http://tinyurl.com/bu2w5a7), including climate sensitivity estimates. You cannot ignore thermal inertia, or for that matter aerosol forcings, in calculating an expected response.”]
Once again you assume that ALL of the 0.8C rise is due to CO2. What evidence do you have to support that idea? Are you saying that any rise is due to CO2 but any non-rise is due to ‘other factors’? How likely is that?
All I’m asking for is some objectivity in evaluating the data. You can use GISS if you want but GISS doesn’t go back to 1850 and GISS wasn’t the dataset used by the IPCC originally. Compare apples with apples. Be objective. You can’t find any real-world evidence to support your view because there isn’t any. Arguing in support of a belief based on an assumption is not being objective. Climate sensitivity ‘estimates’ are a theoretical construct. Models don’t count. Real-world data does. Objectivity will rule in the end, either way. At the moment, there is no real-world validating evidence to support the CO2 radiative theory <i.in the real world.
As for climate4you. Every graph I have linked from that site is backed up by official data from official sources. If you can’t accept that, that’s your problem.
Arfur Bryant – My apologies for not replying before this; other life intervenes.
If you are looking for the forcings since 1750 (the usual criteria in the literature), see http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch9s9-4-1-4.html or http://www.realclimate.org/images/ipcc2007_radforc.jpg – estimate 1750-2000 at about 1.66 W/m^2 forcing change from CO2 alone, or a net forcing of 1.6 W/m^2 including aerosols, clouds, ozone, etc. Sorry if I misinterpreted your post; you seemed to be asking about blank-slate forcings.
You appear to still be stuck on the “CO2 only” meme; that’s clearly _not_ what I referred to. That is a strawman fallacy.
“…we don’t know how much of that 0.8C rise is due to CO2!” – Actually, we do. Over 100%; http://www.skepticalscience.com/jones-2013-attribution.html. And please, don’t run to the “Poisoning the well” fallacy, as I will treat it with the respect it deserves (none).
…there is no real-world validating evidence to support the CO2 radiative theory.” – Aside from all of spectroscopy? Harries 2001 and Chen 2007? You’re headed into ‘Slayers’ territory there, Arfur, denying basic experimental science… the CO2 radiative effect is experimentally confirmed.
Arfur:
Since you don’t give any original references for the data, it is hard to know exactly what you are using but many of the data sets are known not to be sufficient for the purpose of detecting long term trends due to various artifacts due to instrumentation changes and the like. That is why it is a cherrypickers paradise.
Here is a recent discussion of problems with cherry-picked data: http://geotest.tamu.edu/userfiles/216/Dessler10.pdf
Here is a recent review discussing the water vapor feedback and explaining how it is now very well-confirmed (particularly in response to temperature fluctuation on monthly- to yearly-timescales where the issue of artifacts that arise when you try to look at long-time secular trends is absent): http://www.see.ed.ac.uk/~shs/Climate%20change/Data%20sources/1020HumidityVaporWarming.pdf
Two many response to see the below has been suggested.
Wouldn’t it be a better demo if there were no partly warm plate on the right side. This would illustrate that the cold plate on the left slows down the heat loss of the hot plate compared to nothing blocking hear loss of the hot plate on the right side.
Isn’t that what you’re trying to get across?
Arfur Bryant says:
May 20, 2013 at 1:33 PM
“There has been no accelerative rise in global temperature since 1998, and it can be reasonably argued that there has been no rise at all. Why not?
… There is absolutely no evidence to support the conjecture that increased CO2 (and other nGHGs) has caused the rise in OHC (as measured over a relatively short term)”.
Please kindly see:
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/30yrbaseperiods_Nino34.png
The very regular continuous increase of underlying average sea water temperatures at ENSO monitoring region can compare only with continuous increase in GHE, whose natural changes are always oscillating.
In the long term, natural OSCILLATIONS can´t ever beat changes due to causes always acting in the same sense …
In 1998 global mean temp. increased 0.3ºC (relat. to previous year).
In 2010 they were even 0.03ºC higher.
And last year, 2012, they were only 0.06 below 1998.
What firstly quoted from your post is clearly ABSURD and “cherry peaking”.
Rafael Molina Navas, Madrid
Firstly, I note that you haven’t even attempted to answer my prime question.
Secondly…
[“What firstly quoted from your post is clearly ABSURD and “cherry peaking”.”]
To which part of my post are referring? Where exactly have I cherry picked?
Here is the HadCRUt4 global data since 1850:
http://www.climate4you.com/images/HadCRUT4%20MAATand3yrAverage%20Global%20NormalisedFor1979-1988.gif
HadCRUt4 has been manipulated recently. HadCRUt3 shows 1998 was the warmest year.
So I give you the entire HadCRUt global temperature data graph and you give me a 30 year ENSO SST graph and you accuse ME of cherry picking? LOL.
Here are the sea surface temperatures:
http://www.climate4you.com/images/HadSST3%20GlobalMonthlyTempSince1979%20With37monthRunningAverage.gif
Just because you believe in a theory doesn’t make it valid. Try to be objective.
As for global temperature today…
http://www.climate4you.com/images/HadCRUT4%20GlobalMonthlyTempSince1979%20With37monthRunningAverage.gif
HadCRUt3 (which is the dataset used by the IPCC originally) now shows we are 0.3C (global temp) lower than 1998, not 0.06C. Even the manipulated HadCRUt4 shows we are nearly 0.3C lower. In fact ALL of the global datasets show we are currently lower than 1998 by a significant amount.
Go figure.
[“In the long term, natural OSCILLATIONS can´t ever beat changes due to causes always acting in the same sense …”]
In principle, I agree. But you need some real-world evidence to support the idea that CO2 and other nGHGs are the cause of increased temperature. At the moment, the only correlating evidence is between 1975 and 1998. And even that assumes ALL the warming in that period is due to CO2 etc…
Objectivity please.
How much of the GHE is due to CO2?
There is a better way to look at it which may deal with some of the objections and confusions.
The primary radiating source for a planet is the single top most layer of molecules of the solid surface and the single bottom most layer of molecules of the gaseous atmosphere.
On average, both are maintained at the same temperature but due to winds arising from air movement there can be large local variations.
That temperature is set by the amount of KE present at that level and the amount of KE is at maximum there because the decline in density with height also involves reducing KE with height in favour of PE which does not radiate.
The topmost layer of molecules of the solid surface radiates a lot more than the bottom most molecules of the gaseous atmosphere despite being at the same temperature because the solid surface is far denser and the amount of radiation from locations at the same temperature is determined by the density of mass at that location.
The solid surface is at a temperature that allows maximum radiation of ,say, 390 units.
Of that 390 about 150 gets absorbed by the atmosphere and returned to the surface by a combination of radiative and non radiative means (where GHGs are present) but only by non radiative means if no GHGs are present.
With or without GHGs the same amount gets returned to the surface if the mass of the atmosphere remains the same. Only the method of its return varies according to the composition of the atmosphere, not the amount returned.
What happens is that the air circulation changes as necessary to juggle between the radiative and non radiative processes so as to maintain the right ToA radiative balance.
The balance of that 390 which is not returned to the surface escapes to space at ToA.
Hence 240 leaving to space if 240 is coming in from space.
The amount leaving to space must equal that coming in from space over time otherwise an atmosphere cannot be retained.
All weather and climate zone patterns at the surface are a consequence of the system constantly juggling between radiative and non radiative energy transfer processes so as to keep the ToA radiative exchange in balance.
As that juggling process goes on the effective radiating level varies in height constantly (along with the height of the entire atmosphere) but the primary source of radiation remains within those two layers of molecules, one at the top of the surface and one at the bottom of the atmosphere.
A rise in effective radiating height (and of the entire atmosphere) means that energy is leaving faster due to the reduction in density all the way up the vertical column (but not at the surface which retains the same density).
A fall means the opposite.
If more GHGs are present then, if they have a net warming effect, the atmosphere tries to retain more energy, the atmosphere then expands,density falls at every height above the surface, the effective radiation level rises and radiation flows through faster to negate the effect.
AGW theory tries to tell us that a rise in the effective radiating level heats the lower layers and cools the upper layers.
It doesn’t.
Such a rise or fall simply alters atmospheric densities so as to let energy out faster or slower and thereby cancel the effect of GHGs. I refer to faster or slower because I am not sure of the net thermal effect of GHGs but either way the atmosphere changes its circulation to negate it.
The change in atmospheric density and volume permits the circulation to change so that the potential thermal effect from the radiative characteristics of GHGs is cancelled out by a change in the balance between radiation and non radiative energy transfer processes.
Stephen says: “The topmost layer of molecules of the solid surface radiates a lot more than the bottom most molecules of the gaseous atmosphere despite being at the same temperature because the solid surface is far denser and the amount of radiation from locations at the same temperature is determined by the density of mass at that location.”
This is not at all correct. The amount of radiation depends on the emissivity, not density. Polished metals have high densities, but emit very little thermal radiation. Ice has fairly low density, but emits rather well. A little bit of water droplets in the air will have a low density, but high thermal IR emissions.
Furthermore, the atmosphere and the surface are not generally at the same temperature.
1) the surface tends to warm from sunlight during the day, so it tends to get noticeably warmer than the air a few meters up.
2) The lapse rate ensures that the atmosphere higher up (on average) will be cooler than the surface.
Since thermal IR typically travels 10’s or 100’s of meters even in the absorption bands of GHGs in the atmosphere, the radiation from the warmer lower layers up to the cooler upper layers will (on average) be greater than the downward radiation.
The variations between the characteristics of materials other than density simply get dealt with by changes in global atmospheric circulation.
“Of that 390 about 150 gets absorbed by the atmosphere and returned to the surface by a combination of radiative and non radiative means (where GHGs are present) but only by non radiative means if no GHGs are present.”
That is one heck of a neat trick how 150 W/m^2 of radiation get absorbed “by non radiative means”! Yes, the Stephen Wilde nonsense-science generator is in good working order.
The temperature at the surface causes convective uplift which converts KE to PE for a cooling effect above the surface.
After the air has cooled it descends back to the surface reconverting PE to KE.
The surface to atmosphere exchange remains steady at 150, the surface temperature achieves 390 and 240 escapes at ToA.
The conversion of KE to PE and back again causes a delay in throughput of energy transmission which allows the surface temperature to rise above that required for ToA radiation out of 240.
The surface doesn’t radiate up at a NET 390. It radiates up at a NET 240 but the other 150 worth of potential upward radiation gets recycled between surface and atmosphere by the KE/PE conversion process.
Upward and downward convection serve the same purpose as DWIR/UWIR would. It simply slows the net rate of upward radiation but does so via a mechanical rather than radiative process.
Sure the surface at 390 tries to radiate up at 390 but the exchange of energy with the atmosphere reduces the net radiative flow to 240 by the time one reaches ToA.
The thing is that if one invokes DWIR/UWIR as the cause of the greenhouse effect then of course one needs radiative gases.
If one instead invokes upward and downward convection converting and reconverting between KE and PE then the entire mass of the atmosphere is the cause of the greenhouse effect.
I prefer the latter explanation since even a GHG free atmosphere would have a lapse rate, convection and a mass induced greenhouse effect.
And of course such a solution will evoke abuse and disbelief from some given the current state of the science.
Stephen Wilde says:
May 21, 2013 at 2:17 PM
I prefer the latter explanation since even a GHG free atmosphere would have a lapse rate, convection and a mass induced greenhouse effect.
—–
so hot gasses rise (convect) but then cannot get rid of heat without a means to radiate (usually provided by the GHGs).
So with hot at top the bottom heats and rises – still cannot radiate etc. Eventually without GHGs the air becomes constant temperature mixed by thermal motion.
Then what?
should also have said the air temperature will eventually equal the ground and net conduction will be zero.
The ground will be the only radiator to space
The gound albedo and temperature will determine the energy radiated The GHG free air will do nothing.
You forgot the descent part. What goes up must come down.
“The surface doesn’t radiate up at a NET 390. It radiates up at a NET 240 but the other 150 worth of potential upward radiation gets recycled between surface and atmosphere by the KE/PE conversion process.”
This claim lies completely outside the laws of physics.
“And of course such a solution will evoke abuse and disbelief from some given the current state of the science.”
Yes, the current state of the science is that it is based on the known laws of physics rather than the laws of physics as Stephen Wilde would like them to be.
My God. Stephen Wilde has written his own version of the laws of physics.
Please, *please* top polluting the Web with your ridiculous, unscientific ideas. You don’t seem to understand much of anything about radiative physics, and are doing great harm to those here who are trying to puzzle their way through the ideas.
In a vacuum please. Otherwise it is another useless experiment.
Stephen incorrectly states that GHG do not heat the lower atm. while cooling the upper atm.
They do.
The mass and gravity induced greenhouse effect results in a lapse rate with warm at the bottom and cold at the top.
Other factors might disturb the slope of that lapse rate at multiple levels but the circulation adapts to restore the gravity and mass induced lapse rate overall
Stephen incorrectly states the AMOUNT of radiation returned does not depend upon the composition of tha atmosphere.
This is RIDICULOUS,. how could anyone reach such a conclusion in the face of ALL the evidence /data /experimentation which shows this is clearly not the case.
Actually I said the amount of ENERGY returned does not depend on the composition of the atmosphere.
Both the amount of radiation reaching the surface and the amount of KE being returned to the surface by descending air can vary but only oppositely to each other.
However the amount of radiation reaching the surface is ultimately determined by the temperature achieved by the air molecules in contact with it and not by a direct downward flux.
Stephen has this not correct at all when you read his latest post.
TRYING TO HAVE THE GHG EFECT CANCELLED OUT. NO.
No, the mass induced greenhouse effect remains. Only the effect of GHGs is cancelled out.
Stephen, it is EMISSIVITY not density which determines the amounts of radiatin emitted. Emissivity being related to composition of the atmosphere.
STOVE- take two stoves both heated to 500 F, place in front of one stove an object with a temp. of 0f and in front of the other stove an object heated from an outside source maintaining a temp. of 100f.
Guess which stove will cool slower. The stove that receives the greater amounts of IR radiation being emitted from the object in front of it ,which would be the warmer object with a temp. maintained at 100f.
Stephen that is the same principal for the GHG effect for the warming of the lower atmospheric levels/surface. The IR amounts greater due to GHG, in contrast to if no GHG were present,which in turn have the effect of causing the surface of the earth to cool less, then if there were no GHG’S present.
The greater amounts of IR making the surface of the earth less cold, not actually warming the surface of the earth.
It makes sense and it has been demenstrated right on this web-site many times by Dr. Spencer through data, experimentation, and observation.
Without excepting a GHG effect, you can’t account for the earth/climate system and how it might change.
You don’t get a lapse rate between stoves. The analogy is not applicable.
Emissivity differences due to composition variations get dealt with by circulation changes.
There are two problems with all these analogy’s and the test proposed by Roy;
1) whilst most will agree that back radiation from a cooler object will slow cooling of a warmer one this does not in any way quantify this cooling relative to conduction and convection. Conduction and convection are massively more effective at moving heat than radiation which is why all such experiments need to performed in a vacuum to get any form of accurate result. Everything else in daily use that involves heat relies on conduction and convection to transfer the heat with radiation purely an issue of incidental loss. This also holds in the climate with most heat being transferred globally by heated molecules conducting that heat to and from water vapour, surface etc.
2) the atmosphere is not a single radiating surface and it’s characteristics will be very different from a single radiating surface. The decreasing density moving away from the surface will absolutely be an encouragement for radiation to flow away from the surface and make it difficult to return. Each layer of molecules provides an increasing barrier when traveling towards the surface and a decreasing barrier when traveling away. In mechanical terms the IR has to flow from surface to space; there is no other alternative. What brings heat back to the surface is the circulation of the air and conduction.
“What brings heat back to the surface is the circulation of the air and conduction”
Yes.
And radiation is simply a consequence of that.
Iansview,
[“Conduction and convection are massively more effective at moving heat than radiation which is why all such experiments need to performed in a vacuum to get any form of accurate result.”]
I agree. Moreover, when one considers that, in a well-mixed atmosphere, each CO2 molecule is surrounded by about 2500 non-radiative molecules (the actual figure can be argued but it is a lot!) that can be warmed by conduction (particularly form the surface), the contribution of conduction to the ‘Atmosphere Effect’ has been undervalued compared with radiation IMO.
This is why I keep asking the question “What is the contribution of CO2 to the ‘GHE’?”
Nobody seems to want to answer.
Arfur:
(1) Yes, nobody (except a few skeptics) disagree that when a CO2 molecule absorbs radiation, it is quickly thermalized by collisions with the molecules around it, except in the very tenuous outer reaches of the atmosphere (thermosphere, I think). You are not saying anything new there.
(2) It is a simple first-year physics exercise to take the observed lapse rate of 7.5 K per km and use the equation for conduction to determine what sort of rate of conduction you get given the conductivity of air k = 0.026 W/[m*K]. The answer is ~0.0001 W/m^2. So, in fact, conductivity in the atmosphere is completely negligible compared to radiation and convection away in transporting heat from the surface up in the atmosphere. [The only place conduction plays a significant role is right at the Earth/atmosphere interface where the temperature gradients can be large enough to get more significant heat transfer.]
(3) Convection (including evaporation / condensation) is a much more important heat transfer mechanism but one whose efficiency at cooling the Earth’s surface is limited by the fact that when lapse rates are less steep than the adiabatic lapse rate, the atmosphere is not unstable to convection. Hence, convection can only go so far in cooling the surface.
(4) As for your question about the role of CO2, you can look this up, but as I recall, radiative transfer calculations show that CO2 is responsible for about 10-20% of the GHE. The reason for the range is not primarily uncertainty but that the question is ill-defined because of the overlapping effects of the various GHE absorption bands: If you start with an atmosphere without greenhouse effect and add CO2 (while not allowing composition to change in any other way), you get about 20% of the GHE. If you start with the current atmosphere and remove CO2 (while not allowing composition to change in any other way), you remove about 10% of the GHE. However, the reality is that the composition of the atmosphere would change: Removing the CO2 and the other non-condensing GHE’s would reduce water vapor and it would also increase land ice albedo, so at the end of the day, simulations predict that you end up losing almost the entire greenhouse effect.
Joel,
(1) Why do you say [“when a CO2 molecule absorbs radiation, it is quickly thermalized by collisions with the molecules around it…”]? The point is that it is the other (non-radiative) molecules that are ‘thermalized’ by conduction. As there are far more of these molecules, the warming by conduction is greater than the CO2=AGW theory gives credit.
(2) The lapse rate is not a cause, it is an effect. If conduction is so much less of an effect than radiation, why hasn’t the planet warmed in correlation with the increase in radiative gasses? You are arguing from an assumption that your theory is correct. This is contrary to the scientific method. The data indicates that radiation is a very small contributor, particularly in the lower atmosphere. (See 4)
(3) Convection is not really a heat transfer mechanism, is it? It is a heat transport mechanism. Convection transports air which is at a different temperature to surrounding air, upwards for warmer air and downwards for cooler air. Convection does not make surrounding air warmer or colder; that is the job of conduction or radiation. You make a big play about convection being limited by the lapse rate. Although that is technically correct, the percentage of the globe’s atmosphere which has a lapse rate shallower than adiabatic at any one time is relatively small. Any view of the planet from space will tell you that. IMO you are clutching at straws there. Convection will actually still occur in shallow lapse rates but it will be dampened by the difference between ELR and D or SALR, normally over relatively small altitude changes. You very rarely find a neutral or inversive lapse rate extending to high altitudes.
(4) Joel, I have tried to look this up! All I get is ridiculous figures such as 26% (Trenberth & Schmidt), or 20% (+5% for other nGHGs) from Lacis. These figures are a result of model output. I can find no real-world figures for the contribution of CO2 to the ‘GHE’. This is such a crucial point, I am amazed it hasn’t been investigated more thoroughly. The question is not ill-defined at all. It is very simple. You simply cannot say the CO2 has a significant effect on global temperature and then run away from explaining how this significant player has no evidential support.
[“If you start with an atmosphere without greenhouse effect and add CO2 (while not allowing composition to change in any other way), you get about 20% of the GHE.”]
Eh? How can there even be a ‘GHE’ if you start with no radiative forcer (I discount the other nGHGs at this stage as they would have been insignificant in such an atmosphere)? What you are admitting to by saying that is Stephen Wilde (and the Slayers) has been correct all along, in that the majority of the ‘Atmosphere Effect’ is from non-radiative factors! A whopping 80% in fact! All that remains is to prove the contribution from CO2 is actually 20% or maybe less. If much less, then the radiative theory of AGW is irrelevant. So… 20% of the current ‘GHE’ is 6.6C (IPCC says GHE =33C). 20% of the ‘GHE’ in 1850 was 6.44C (32C-0.8=32.2C). So a 40% increase in CO2 has increased the CO2 contribution to the GHE (Atmosphere Effect) by 0.16C. This doesn’t seem very significant to me. You cannot assume that ALL of the 0.8C rise is due to CO2, as that would deny any natural factors completely, and there have been similar warmings before the late C20th warming. Even at 10% contribution for CO2, the figures don’t support the radiative theory (3.3C to 3.22C = 0.08C). If you want to use a different percentage back in 1850, you need to provide some quantitative evidence for doing so.
Do you see now why it is so important for scientists to address this question? Without an accurate figure for the contribution of CO2, the argument will just run around in circles because both sides are arguing from an assumption. We need facts (evidence), not assumptions! Climate scientists can’t just chuck figures like 26% (CO2) around and then run away from answering the obvious questions that should follow…
Regards,
Arfur
Arfur,
Your latest response is, unfortunately, a morass of utter confusion:
(1) I don’t think many people would refer to the thermalization process as conduction. “Conduction” is usually in reference to heat being transported on macroscopic scales, not the sort of microscopics by which the energy becomes uniform on very small length scales. And no, one cannot credit conduction for the absorption of the IR radiation.
(2) You say: “The lapse rate is not a cause, it is an effect.” Heat will be conducted according to the equation that the rate of heat conduction across an area A is equal to k*A*dT/dl where dT/dl is the temperature gradient. I have given you the correct calculation of the rate of conduction that will occur due to the decrease in temperature with height in the atmosphere (except that I got it off by a factor of two…It should have been 0.0002 W/m^2, for what its worth.) “If conduction is so much less of an effect than radiation, why hasn’t the planet warmed in correlation with the increase in radiative gasses?” The planet has been warming as greenhouse gases have increased, although there are other effects too (such as aerosols). But, the issue of the amount of warming is one that gets us in to talking about feedbacks and climate sensitivities and is frankly off-topic. You seem to have a hard time staying on topic.
(3) “You make a big play about convection being limited by the lapse rate. Although that is technically correct, the percentage of the globe’s atmosphere which has a lapse rate shallower than adiabatic at any one time is relatively small.” Which proves my point!!! That is exactly the point: The atmosphere is not driven to an isothermal structure by convection exactly because convection does not reduce the lapse rate below the adiabatic lapse rate. If it were driven to an isothermal configuration, then it would neutralize the greenhouse effect but since it doesn’t do so, convection only reduces (by about a factor of 2 apparently) what the greenhouse effect would be in its absence. That was the mistake the Nikolov and Zeller made when they put convection into a simple shell model: They did it in a way that by their own description drove the atmosphere to an isothermal state and then they marveled about the fact that this caused the greenhouse effect to disappear. If they had actually read a climate science textbook, they would have known that this is exactly what one would expect to happen if you put convection into the model in an unphysical way that drives it all the way to an isothermal state.
(4) You complain that all the figures for the relative effect of CO2 to the greenhouse effect come from modeling. Well, what else are they supposed to come from? Are they supposed to build a replicate of Earth and then remove the greenhouse gases? Yes, various sciences like astronomy and climate science can’t do laboratory experiments on their entire system. That doesn’t stop them from verifying their calculations, e.g., by comparing the modeled spectra to the observed spectra seen from satellites. “So… 20% of the current ‘GHE’ is 6.6C (IPCC says GHE =33C). 20% of the ‘GHE’ in 1850 was 6.44C (32C-0.8=32.2C). So a 40% increase in CO2 has increased the CO2 contribution to the GHE (Atmosphere Effect) by 0.16C.” That calculation makes no sense at all. Why are you assuming that the contribution of CO2 remained fixed at exactly 20% of the GHE when its atmospheric concentration rose by 40%? All of the increase in temperature for an enhanced greenhouse effect is due to the increase CO2 (and the other trace gases) and the feedbacks from these…and some of it has been offset by increases in aerosols that have caused cooling.
Like I said, your post is just a lot of confusions and besides-the-point issues, clearly driven by your ideological agenda to show that CO2 is insignificant.
You said: “What you are admitting to by saying that is Stephen Wilde (and the Slayers) has been correct all along, in that the majority of the ‘Atmosphere Effect’ is from non-radiative factors! A whopping 80% in fact!”
I am having a hard time even understanding your train of thought here? I am talking about CO2 being 20% of the radiative effect with the other 80% of the radiative effect being provided by water vapor, clouds, and the other non-condensing greenhouse gases (CH4, …) And, as I explained, the Lacis paper shows simulations that removing the CO2 (and the other non-condensing greenhouse gases) gets rid of much of the rest of the greenhouse effect because the cooling causes the water vapor to condense out.
Joel,
I’m disappointed. I thought we could have a decent discussion but you seem to want to argue with rhetoric not evidence. Shame.
[“Your post is just a lot of confusions and besides-the-point issues, clearly driven by your ideological agenda to show that CO2 is insignificant.”]
No Joel, I just want you to be objective and not argue from dogma. Its not that I have an ideological agenda, I just don’t see that the ‘Radiation is King’ theory is supported by observed data. Gainsaying each other achieves nothing. To your numbered points:
1. [“I don’t think many people would refer to the thermalization process as conduction.”] Pure pedantry. Conduction can take place in gasses. Would you prefer diffusion? By your last sentence you infer that none of the non-radiative molecules in the atmosphere can be heated, as they cannot be heated by radiation. This means that, according to you, the entire GHE of 33C is formed by radiation almost alone (you say conduction plays a negligible role). Is that your stance? 99.96% of the dry atmosphere is unable to be warmed? Add water vapour and you’ve got, what, 99.96% out of about 101.5% unable to be warmed as you have dismissed low energy collisions? Interesting…
2. [“The planet has been warming as greenhouse gases have increased, although there are other effects too (such as aerosols). But, the issue of the amount of warming is one that gets us in to talking about feedbacks and climate sensitivities and is frankly off-topic. You seem to have a hard time staying on topic.”] Aah, you don’t want to (or you can’t) provide evidence to support your (dogmatic) belief in the veracity of the radiative CO2=AGW theory. Ok, I get it. I’m the one that’s confused… not.
3. [“…this is exactly what one would expect to happen if you put convection into the model in an unphysical way that drives it all the way to an isothermal state.”] Because, of course, all the AGW models have proved to be completely accurate… Oh, wait a minute… Like I said, convection is not really a mechanism of heat transfer. Don’t deflect my point by bringing in random papers. You are the one who said it was a “much more important heat transfer mechanism…”
4. [“Are they supposed to build a replicate of Earth and then remove the greenhouse gases?”] No, that is silly. They are supposed to NOT assume that their/your theory is so correct that they/you are unable to even contemplate that there may be other factors which can result in the observed warming. They/you are supposed to be able to look at the data objectively and see if the data falsifies or supports the theory. THAT’s my biggest problem with your stance. I repeat (again!): unless you can provide evidence to support your ‘theoretical assumption’ that ALL of the 0.8C warming since 1850 is due to CO2 (nGHGs), then you/they are arguing from an assumption. Clear?
[“Why are you assuming that the contribution of CO2 remained fixed at exactly 20% of the GHE when its atmospheric concentration rose by 40%?”] Read my post again. I said that if you didn’t want to use the same percentage then you should provide a figure that you would want to use. Go for it. And stop trying to deflect my argument. Just answer the question.
[“All of the increase in temperature for an enhanced greenhouse effect is due to the increase CO2 (and the other trace gases) and the feedbacks from these…”] Provide evidence to support that statement!
Objectivity Joel, not ideology…
Unfortunately I am not getting the point across so I will just have to await scientific progress on the issue.
Yes…You are such a genius ahead of your time!
Really, get over yourself! You are just spouting completely indefensible pseudo-scientific nonsense.
Joel,
I don’t know whether Stephen is right or not but I do agree with him that the effects of conduction and convection seem to have been sidelined in favour of radiative effects. And yes I’ve read the Science of Doom stuff that relates and I know that convection has not been ignored in the climate models. Still in the real world (heating systems, boilers, cooling towers, hot water storage systems etc) conduction and convection are the real workhorses and radiation is but a bit part player. It doesn’t feel right that it’s been turned on it’s head as far as the atmosphere is concerned. I’m a mechanical engineer and I’m afraid I’m skeptical of theoretical calculation and modeling until the model has been tested in anger. I was involved with a project to design a vertical axis tidal turbine design a few years ago and a CFD model was developed to test and refine the design before a large scale prototype was built. All proven physics, known effects, standard calculations etc. The CFD model identified the power that the turbine should produce in a given flow. However it was nowhere near the mark (out by orders of magnitude) and the modeling process added no value at all. Later changes to design showed that refinements suggested by the CFD model had been massively counter-productive and that the initial design as developed by ongoing testing was far superior. Bottom line is that theory doesn’t always equal practice as I’m sure you realise.
Iansview: It is not like the stuff that Stephen is talking about might be right or might be wrong…It is complete nonsense in violation of the known laws of physics. Admitting to not knowing whether its right or not is selling yourself short…I hope you are educated enough to know pseudo-scientific nonsense when you see it.
As for your statement about conduction and convection vs radiation. The basic undisputed (by any serious scientist) facts are these:
(1) The only way that the Earth system (earth + atmosphere) can send and receive any significant energy from outside is via radiation. Hence, radiation has to play an important role. You can’t just will it away.
(2) Convection (including evaporation/condensation) is indeed a very important heat transport mechanism. Nobody is denying that. However, it obeys some physical laws, one being that it will only go so far in transporting heat up from the surface, namely it will only drive the lapse rate down to the adiabatic lapse rate and no further. For lapse rates below the adiabatic lapse rate, the atmosphere is stable and convection does not occur. This is why convection can reduce the greenhouse effect (from what it would be if there were no convection) but not eliminate it.
(3) Conduction is simply too slow a heat transport mechanism to play much of a role in the atmosphere except on short length scales at the Earth/atmosphere boundary.
Arfur Bryant
(May 21, 2013 at 1:47 AM)
My first quote from your post was clearly:
“There has been no accelerative rise in global temperature since 1998, and it can be reasonably argued that there has been no rise at all. Why not?”
You mention last 15 y., and I 74, not 30 (each line IS a 30 y. average).
Have you really observed the ENSO monitoring region graph?
If we look at:
http://www.ncdc.noaa.gov/cag/time-series/global
at the bottom, we can see that:
a) In the three years previous to 1998 temperatures were between 0.3 and 0.46 ºC lower than in 1998 (a clear maximum most likely due to the concurrence of two or more factors).
b) Since 1999 temperatures have always been higher than in those three years, and in 2010 even 0.03 ºC higher than that 1998 maximum.
If somebody says that since 1998 temperatures haven´t increased at all, for me it´s a clear case of misleading cherry picking …
And regarding GHE, something utterly proved in labs, what I say is that most graphs are irregularly ondulated, with ups and downs. But the regularity of changes shwon through the graphs of the link is very similar to the regularity of GHG increase, even after 1998.
Rafael,
I cannot open that link to show the global temperature but it appears to start at 1880. The dataset I provided you with is HadCRUt which starts at 1850 and was the IPCC original dataset. Why do you keep talking about ENSO regional data when my first sentence is clearly about global temperature?
What I stated was [“There has been no accelerative rise in global temperature since 1998, and it can be reasonably argued that there has been no rise at all.”]
I stand by that statement. Where do you see an acceleration in global temperature? Please note I said “it can be reasonably argued…” about the flattening since 1998. HaCRUt3 still has the warmest year as 1998. HadCRUt4 shows 2010 but makes an enormous change in the anomaly in that year from HadCRut3. Either way, every single global dataset shows that the temperature today is significantly lower than 1998, so my comment stands.
Please also note that you still have not addressed my question about the contribution of CO2 to the ‘GHE’.
I politely request that you address this specific point.
Please, in the page of the link, choose “globe” not “US”, when reading my recent post
Rafael,
I tried that.
Thinking through that density /emissivity point.
Emissivity will determine how long a material needs to be irradiated at a given rate in order to reach the maximum possible temperature for that material.
Density will determine the maximum temperature that will be reached by that material at that given level of irradiation.
For an atmosphere around a planet the circulation can adjust to remove the effects of emissivity but not the effect of density.
Anyway, I’ll have to leave it there since I don’t expect agreement and I have other commitments for the next few days.
Hello Dr. Spencer,
I am a physicist, and I occasionally visit your site.
I just came across this today and thought I would add my 2 cents from a physicists perspective.
I don’t have time to go through all your emails on the “experiment” so perhaps someone has already taken the “physics” point of view and this is redundant.
Your experimental design is not the best but o.k.
What you will find if you do the experiment “correctly” (not to denigrate, but to clarify) is that the plate that is hot and the plate that is cold will eventually reach the same temperature. That is, heat will be transferred radiatively from the hot plate to the cold plate until the two are in thermal equilibrium.
I would choose a spherically symmetric geometry instead of a planar geometry with a hot solid sphere on the interior surrounded by a cooler spherical “shell”. That way the radiation is contained geometrically.
I would also place the experiment in an evacuated space so that no convection occurs and obviously thermally insulate the sphere from the spherical shell so that no conduction occurs. So the only heat transfer process that can occur is via radiation.
The experiment I have described would be difficult to build, so I guess you could start with the planar geometry, but, obviously, the radiation field of the hotter object is not “contained” then and there is also the possibility of convection currents affecting the results.
Dr. Rich Gibson
Rich,
You might be interested in the idea I posted earlier in this thread for a simple, cheap way to do what you suggest — a light bulb!
http://www.drroyspencer.com/2013/05/a-simple-experiment-to-show-how-cool-objects-can-keep-warm-objects-warmer-still/#comment-79927
The “hot plate” (ie filament) is surrounded spherically by the “cold shell” (the glass bulb). The space in between is a very good vacuum. Run the filament at a low power (a few 100 C) and put the bulb in contact with water (from 0-100 C) to control the back radiation. The filament should change temperature — which is easily confirmed by a change in resistance.
(Since writing the first post, I realized that most “standard size” bulbs are partially filled with inert gas. But smaller “flashlight bulb) are typically vacuum sealed.)
Rich
From a classical physics point of view I would agree.
The challenge Roy is addressing is how to set up an experiment that is easily demonstratable by a lay person with common materials and a radiation thermometer and gives obvious results to address the critical misunderstanding that cold and warm objects can still radiate heat to hot objects and affect the rate of cooling of the hot object – cf space vs a greenhouse gas warmed atmosphere to the earth’s surface.
I do of course realise that a surface at a temperature that would radiate at 390 has to shed its energy one way or another.
The radiative theory is that 390 goes up towards ToA but 150 gets absorbed by GHGs and returned to the surface leaving 240 going out to space.
My view is that 240 goes up from the surface and out to space as radiation but 150 gets absorbed by the atmosphere via conduction and convection and then gets returned to the surface the same way leaving 240 going out to space.
The former cannot be right because we see real world evidence of the effects of conduction and convection all the time.
Stephen,
Conduction and convection don’t absorb electromagnetic radiation. You are still talking nonsense.
a hot surface transfers energy to the air by conduction. The air rises and converts KE to PE which is a cooling process.
The energy transferred via conduction is not then available for radiation unless you think it can be in two places at once.
Think of two stoves some distance apart.
If there is conduction and convection going on between them the energy removed by that process will not reach the other stove by radiation.
At some sufficient distance the conduction and convection would result I neither stove receiving radiation from the other.
“The energy transferred via conduction is not then available for radiation unless you think it can be in two places at once.”
Again, you are making up your own physical laws. The actual physical laws say that there is not a cap on the total energy transferred. The 390 W/m^2 is the amount radiated by a surface at ~288 K. Any amount transferred by conduction to the atmosphere is in addition.
Your argument about there only be a limited amount of energy available just translates into the fact that a surface that is both radiating and conducting heat away will cool down more rapidly (which is why you blow on a spoonful of hot soup to cool it down more rapidly)…Or, if it is in a steady-state configuration, it will be at a different temperature in order that the total amount of energy it loses and the total amount it gains are equal. (In the case of the Earth, this means that the temperature of the Earth would be hotter if there were not convection…Again, the point being that convection can reduce but cannot eliminate the greenhouse effect (because it can only drive the lapse rate down as far as the adiabatic lapse rate).
“At some sufficient distance the conduction and convection would result I neither stove receiving radiation from the other.”
The reason that the stoves will be receiving less radiation from each other is simply because they are further apart and the intensity of radiation will drop off as 1/r^2 (or, to put it another way, if one stove is far away from the other, only a small fraction of the solid angle one stove sees will be the other stove, most of the rest of the solid angle will be other surroundings). [I suppose that absorption by the greenhouse gases in the atmosphere could also play a role, although I think the main factor is just the 1/r^2 fall-off.]
Stephen, You can’t just make up physical laws to fit what you want to believe. The actual physical laws are well-confirmed. Your incorrect versions are simply based on elementary misunderstandings like the ones that I have pointed out above.
Joel Shore says, May 23, 2013 at 4:22 PM:
“Again, you are making up your own physical laws. The actual physical laws say that there is not a cap on the total energy transferred. The 390 W/m^2 is the amount radiated by a surface at ~288 K. Any amount transferred by conduction to the atmosphere is in addition.”
Joel, you’re the one inventing physical laws to suit your agenda. Where is this ‘law’ of yours stated? That conduction/convection and evaporation from a surface after absorption only comes ‘in addition to’ or ‘on top of’ (after?) radiative loss? That an object experiencing convective heat loss would still radiate directly according to its physical temperature as if it were a black body in a vacuum?
The Stefan-Boltzmann Law cares only about temperature differences between bodies. NOT radiation differences.
Why would it otherwise only care about the emissivity (and the radiating area) of the warmer object actually transferring energy (to the cooler one) and only the temperature of the cool one? Let’s have a look:
P = eσA(T^4 – Tc^4)
http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/stefan.html
Notice how this radiative heat transfer equation does not care how much the cool object would’ve radiated without the warmer one present. There is no real 350-324 radiative exchange here. The only real radiative flux would be the 26 W/m^2. And it would go from warm to cool (surface to atmosphere).
How can I say this? ‘HEAT’ is defined as the energy transferred from a hot to a cold system (object). It is SOLELY dependent on the temperature difference between the two systems. And that’s what the equation above shows us. Heat transfer is NOT dependent on the difference in the potential radiative fluxes of the two individual systems if isolated from each other. Why? Because that could leave you in a situation where the cooler object actually radiates more than the warmer one. And then the net transfer would go from cool to warm (!):
http://www.drroyspencer.com/2013/05/time-for-the-slayers-to-put-up-or-shut-up/#comment-79039
If you look closely at the equation above, you will see that there is only ONE ‘e’ value and ONE ‘A’ value. They both belong to the hot object.
HyperPhysics (link above) states it like this: “The relationship governing radiation from hot objects is called the Stefan-Boltzmann law: P = eσA(T^4 – Tc^4).”
Kristian,
The hyperphysics textbook does not have a lot of detail about that formula. I invite you to peruse real physics textbooks that you can find at the library or a university bookstore.
For example, Young and Freedman, “University Physics” (12th edition, 2008) says:
“While a body at absolute temperature T is radiating, its surroundings at temperature T_s are also radiating, and the body absorbs some of this radiation. If it is in thermal equilibrium with its surroundings, T = T_s and the rates of radiation and absorption must be equal. For this to be true, the rate of absorption must be given in general by H = AeσT_s^4. Then the net rate of radiation from a body at a temperature T with surroundings at temperature T_s is
H_net = AeσT^4 – AeσT_s^4 = Aeσ(T^4 – T_s^4) (17.26)
In this equation a positive value of H means net heat flow out of the body. Equation (17.26) shows that for radiation, as for conduction and convection, the heat current depends on the temperature difference between two bodies.”
As another example, Knight, Jones, and Field , “College Physics” (2nd edition, 2010) says:
“When you sit in the sun, your skin warms due to the radiation you absorb. Even if you are not in the sun, you are absorbing the radiation emitted by the objects surrounding you. Suppose an object at a temperature T is surrounded by an environment at a temperature T_0. The net rate at which the object radiates heat energy – that is, radiation emitted minus radiation absorbed is
Q_net/delta_t = eσA(T^4 – T_0^4) (12.34)
This makes sense. An object should have no net energy transfer by radiation if it’s in thermal equilibrium (T = T_0) with its surroundings. Note that the emissivity e appears for absorption as well; objects that are good emitters are good absorbers.”
And, just in case you think this is a quirk of 21st century physics textbooks, here is what is said in my old college textbook Serway, “Physics for Scientists and Engineers” (1983):
“A body radiates and also absorbs electromagnetic radiation at rates given by Eq. 17.11. If this were not the case, a body would eventually radiate all of its internal energy and its temperature would reach absolute zero. The energy that the body absorbs comes from its surroundings, which also emit radiant energy. If the body is at a temperature T and its surroundings are at a temperature T_0, the net power gained (or lost) as a result of radiation is given by
P_net = eAσ(T^4 – T_0^4) (17.12)
When a body is in equilibrium with its surroundings, it radiates and absorbs energy at the same rate, and so its temperature remains constant. When a body is hotter than its surroundings, it radiates more energy than it absorbs and so it cools. An ideal radiator or ideal blackbody, (e = 1) is one which absorbs all of the energy incident on it (and hence reflects no energy). Therefore, a black body is also a good emitter of radiant energy. Likewise, a highly reflecting surface (e approximately equal to 0) is a poor absorber and a poor emitter of radiant energy.”
“Heat transfer is NOT dependent on the difference in the potential radiative fluxes of the two individual systems if isolated from each other. Why? Because that could leave you in a situation where the cooler object actually radiates more than the warmer one. And then the net transfer would go from cool to warm (!):
http://www.drroyspencer.com/2013/05/time-for-the-slayers-to-put-up-or-shut-up/#comment-79039 ”
I had missed that little example that you gave up-thread. However, your example just illustrates what I have said all along, which is that the fact that radiative emission is an increasing function of temperature and that Kirchhoff’s Law of Radiation holds is enough to guarantee that the 2nd Law will always be obeyed. You admit that the warmer object that has emissivity 0.5 also has absorptivity 0.5 and hence won’t absorb all the radiation from the cooler but then try to dismiss this as somehow not being relevant (because you don’t understand the definition of heat). That body will reflect half of the radiation that is incident upon it. So, in fact, it is exactly what is relevant: Kirchhoff’s Law of radiation is a necessary condition for radiative transfers to satisfy the 2nd Law.
Kristian says: “Why would it otherwise only care about the emissivity (and the radiating area) of the warmer object actually transferring energy (to the cooler one) and only the temperature of the cool one?”
This is actually an intelligent question: Why does the emissivity of the surroundings not enter into things? I believe the reason is rather subtle. For the surroundings, the emissivity can essentially be ignored for the following reason: Imagine you have some part of the surroundings whose emissivity is only 0.5. You might think that this means that it will only emit half of what you expect toward the object. However, remember that this means that its absorptivity is also only 0.5 and hence it will be also be reflecting radiation that was emitted from other parts of the surroundings and incident upon it. So, in the end, in most situations at least, the surroundings can be well-approximated by assuming that they have emissivity 1. There are probably some special cases one can come up with, like an object surrounded completely by a reflective metal very close to it where this approximation breaks down…but in the most common situations, this is not the case.
This corresponds well to how ideal blackbodies are even sometimes defined as being cavities of an object ( http://www.embd.be/quantummechanics/black_body_radiation.html ) where the radiation bounces around a lot and this leads to an effective emissivity of 1.
So regular mixtures of gases in the atmosphere at 1 Bar can be approximated as a black body cavity huh?
Just to note for everyone who keeps bringing up Kirchoff, that only applies in thermal equilibrium, and is not a universal rule applicable in all situations.
It is indeed possible to have bodies which absorb more at given wavelengths than they emit, it is possible to have bodies which broadly absorb more than they emit thermally (superconductors have this property in some cases), and so forth.
For a non-black body which is not in thermal equilibrium, Kirchoff does not automatically apply, perhaps you should read those text books before citing them blindly, Joel?
Stephen Wilde
Re: “150 gets absorbed by the atmosphere via conduction and convection and then gets returned to the surface”
Please explain your hypothesis, and especially how you propose to have “convection” cause hot air to descend, seeing that hot air is less dense than cold air.
It cools and then descends. Basic meteorology. Low and high pressure cells.
Joel/Roy,
A question re the Unit of w/m^2 which is used in all the Trenberth papers etc but that I cant find explicitly answered. It is used for energy at the TOA, at the surface, and also within the atmosphere. When used at the TOA is it a m^2 at that altitude, or is it based on a m2 at the surface. i.e. If for example there are 1000 m^2 of earth surface and 1500 m2 of TOA (there is obviously a lot more m^2 due to the larger radius of the sphere at TOA), does the unit always equate to an equivalent m^2 on the surface (e.g. the TOA is split up into 1000) for the purposes of calculation?
Don’t worry….just seen the difference is not significant!
Roy
Great proposed experiment.
Yes the hot plates will cool at different rates due to the difference in heat radiated back from the cold or luke warm plates to the hot plates.
(The thermodynamic heat flows from hotter to colder argument only holds for the system aggregate, not for on the individual components.)
Corresponding heating/cooling rates:
With just a few more measurements, you could also show different rates of warming on the two cold sections proportional to the different cooling rates on the two hot sheets.
Ambient temperature
Recommend the ambient temperature be a nominal 75F instead of 80F as that would give you a 2x difference in temperature (and closer to the mid continent indoor temperature rather than southern indoor temperature).
Option: Cool plate
You could show an alternative cool plate by cooling in a bucket of ice water for the 0C or ~ 32 F.
That would show a refinement difference in the difference to a cold vs cool plate.
Insulation Refinement:
You could improve the experiment by adding Styrofoam around all sides and the bottom, and two half sheets of styrofoam on the top. Then lift one or the other half off the top to take your radiative measurements. That would make a small difference by reducing extraneous radiation/convective affects, but it would not change your core demonstration.
Hot temperature Option:
You could increase the difference by heating the hot panels to ~ 212 F by putting in boiling water – but with higher risk of experimenters burning themselves.
The hot bath water temperature of 150 F is the safer option and still gives you about 2x difference in radiative cooling.
SI vs Imperial
In reporting the results, suggest showing temperatures both in deg C and deg F.
I agree on the nonsence that these people keep trying to put upon this message board. They are not ever going to change their minds nomatter what evidence and facts is presented to them.
Joel,
This questions is puzzling me. Do you know the answer?
If the atmosphere (let’s assume it’s a single layer) consisted of purely oxygen and nitrogen how would the heat conducted from the surface to the atmosphere escape?
Would;
a) the heat passed to the atmosphere not be able to escape in the absence of GHG’s and as a result the atmosphere would get hotter and hotter.
b) the heat would be quickly radiated (by IR and MW presumably) to space as there are no GHG’s to slow it’s passage and as a result the atmosphere would be much cooler than it is now.
c) neither of the above and some other mechanism would be employed.
In my opinion it just should keep warmer the surface which should be at almost the same average temperature as with GHGs.
It just should change the place where the IR exited to the outer space. Instead of exiting almost from the surface and a little from the atmosphere, it should exit all at the surface.
And it still should have a lapse rate due to the gravitational field.
But that’s just my own opinion.
Have a nice day.
Massimo
Agreed
Iansview,
Good question. There has been lots of debate here and other places about what such an atmosphere would look like. I think that this case is a somewhat bizarre “singular” case which is actually more complicated to figure out than the case where there are some greenhouse gases.
Here is what we do know: The fourth root of the average surface temperature would be 255 K so that the surface would radiate 240 W/m^2 back out into space (assuming, for simplicity, that the albedo of the Earth is still 0.3).
As for the atmosphere, it seems a bit trickier. There are people like Konrad who have argued that there would be some sort of “ratcheting” up mechanism on atmospheric temperatures whereby the temperature of the atmosphere near the surface would be warmed during the day and convect up, transferring heat up into the atmosphere but that at night when the surface cold, it would create a stable situation so that although the atmosphere immediately near the surface would cool, this cooling could not be efficiently transferred up into the atmosphere. Hence, the possibility exists for a sort of discontinuity between the surface temperature and the temperature of the atmosphere a little above the surface.
I haven’t yet been convinced of either the correctness or incorrectness of this argument. It does neglect a couple of things: (1) The air that gets convected up would cool by adiabatic expansion. (2) [A point made by Tim Folkerts, I think.] Air can’t rise up everywhere without descending in other places, so although there is no natural convective force causing the hot atmosphere to be transported across the cooler ground at night, these sort of subsistence zones might do the trick.
So, the honest answer is that I remain somewhat agnostic at the moment about the exact state of the atmosphere in this singular case, although as I noted, the surface temperature of the Earth is most definitely constrained by radiative balance to be considerably cooler than it is now.
Hi Iansview,
You present a good speculative question. It should be noted that creating an Earth atmosphere comprised only of oxygen and nitrogen, proves extra-ordinarily improbable on a moments reflection. Two reasons come to mind.
1. The sun’s rays create ozone (GHG) from oxygen in our atmosphere continuously.
2. The earth continuously emits/vents methane (and other natural gas hydrocarbons), sulfur dioxide and no doubt other GHG’s continuously.
Many other natural processes likely produce them as well.
To your first point:
“a) the heat passed to the atmosphere not be able to escape in the absence of GHG’s and as a result the atmosphere would get hotter and hotter.”
Diatomic gas compounds, like oxygen and nitrogen, as far as I know can radiate the heat they convey as a result of surface contact. They simply cannot absorb IR. Nothing prevents them from subsequently radiating energy after contact with the surface. You mentioned MW radiation. If oxygen cannot emit MW, then how does Roy measure atmospheric temperatures using MSU (Microwave Sounding Unit) satellites? Presumably, oxygen molecules can emit MW.
“b) the heat would be quickly radiated (by IR and MW presumably) to space as there are no GHG’s to slow it’s passage and as a result the atmosphere would be much cooler than it is now.”
Probably correct. It would be interesting to know how unimpeded radiated IR transfer to space would effect other processes like convection.
“Diatomic gas compounds, like oxygen and nitrogen, as far as I know can radiate the heat they convey as a result of surface contact. They simply cannot absorb IR. Nothing prevents them from subsequently radiating energy after contact with the surface. ”
John,
Well, I think for the same reason that they don’t couple to electromagnetic radiation to absorb it, such molecules won’t radiate it either (basically, the ground state of the molecules and even the excitations of relevance for the far-IR wavelengths lack a dipole moment). Or, to look at it another way, Kirchoff’s Law for Radiation says that emissivity has to equal absorptivity at a given wavelength.
It should be said, however, that in reality it is only purely isolated molecules that can’t emit at all. Once they are in a gas and have interactions / collisions with other molecules, some emission can occur…although this is a pretty small effect at atmospheric pressures.
And, I think you are right that, practically-speaking, it is probably difficult to get any significant atmosphere without some greenhouse gases in it.
“Well, I think for the same reason that they don’t couple to electromagnetic radiation to absorb it, such molecules won’t radiate it either (basically, the ground state of the molecules and even the excitations of relevance for the far-IR wavelengths lack a dipole moment). Or, to look at it another way, Kirchoff’s Law for Radiation says that emissivity has to equal absorptivity at a given wavelength.”
Hi Joel,
Thank you for the information, especially in regards to Kirchoff’s Law. However, keep in mind (as you seem to realize) I merely stated that after diatomic gas compounds convey heat from the surface they can radiate the acquired energy. I did not state that the energy subsequently radiated by the diatomic gas compounds would be in the IR wavelengths. While the Earth and covering atmosphere absorb 240w/m2 (considering the Earth’s albedo) averaged over the surface and emit the same back to space, the radiative wavelengths of incoming solar radiation differ greatly from the outgoing radiation emitted from the Earth and surrounding atmosphere. For example, as you may know better than I, incident solar IR has (if I remember correctly) approximately five times the energy and/or one fifth the wavelength of IR emitted from the planet surface.
You also wrote:
“It should be said, however, that in reality it is only purely isolated molecules that can’t emit at all. Once they are in a gas and have interactions / collisions with other molecules, some emission can occur…although this is a pretty small effect at atmospheric pressures.”
Theoretically, all matter emits energy unless at a temperature of absolute zero. The Hubble telescope supposedly records IR background radiation even from the deepest regions of space. The universe appears to be a perfect radiator. Apparently, as far as anyone can tell, matter will at any point in the known universe emit energy.
Thanks again for your post.
Jupiter, Saturn, Uranus, Neptune, all are examples of “significant atmospheres” without greenhouse gases.
The Sun is as well.
O2 and N2 absorption lines to ~1000 microns.
O2/N2/CO2/H2O lines to ~25 microns.
Hi Max,
Good point. However, keep in mind three facts. First all the planets you list just happen to be gas giants, apparently not solid body planets with an atmosphere like Venus, Earth and Mars. Second the gas giants do have greenhouse gases but in small proportions (one could say the same about Earth). Jupiter has ethane and I believe hydrogen sulfide for example. Moreover, consider that of the three solid body planets with atmospheres the Earth is the only one with a primarily diatomic (oxygen and nitrogen) atmosphere. The other two have atmospheres comprised almost completely of greenhouse gases, over 95% CO2. Volcanically active planets can spew out a great deal of greenhouse gases. For solid body planets with atmospheres the Earth proves the exception to the rule atmospherically.
Iansview,
Bear with me one minor correction. While atmospheric diatomic gas compounds like oxygen and nitrogen should not impede radiated IR from the Earth’s surface they may very well impede MW radiation from the surface. If as Joel pointed out regarding Kirchoff’s Law emissivity must equal absorptivity at a given wavelength then oxygen molecules should be able to absorb outgoing MW radiation seeing as I illustrated above they emit MW radiation. It should be obvious to most that the GHG label, applies to all gas compounds at varying wavelengths.
Kirchoff applies to black bodies in thermal equilibrium, the concept of emissivity emerges from comparing actual absorption and emission spectra with the theoretical bodies Kirchoff considered.
Total emissivity and spectral emissivity are not the same thing for a non-black body, and absorptivity of a transparent medium is not something you can trivially approximate with a black body.
Hi Max,
Thanks for your input. You claimed:
“Total emissivity and spectral emissivity are not the same thing for a non-black body, and absorptivity of a transparent medium is not something you can trivially approximate with a black body.”
True. Strange you should make this claim in response to my post since I merely refer to and expand on Joel’s claim to the effect:
“Well, I think for the same reason that they don’t couple to electromagnetic radiation to absorb it, such molecules won’t radiate it either (basically, the ground state of the molecules and even the excitations of relevance for the far-IR wavelengths lack a dipole moment). Or, to look at it another way, Kirchoff’s Law for Radiation says that emissivity has to equal absorptivity at a given wavelength.”
Funny, you didn’t make the same claim in response to his prior post regarding the IR absorptivity of a transparent medium (oxygen and nitrogen). In any case, oxygen will apparently absorb MW radiation. Joel used Kirchoff’s Law to support a conclusion regarding the lack of IR absorptivity of diatomic elemental gas compounds like oxygen and nitrogen. Iansview in a post above seemed to assume for a reason I cannot fathom that MW radiation would not be impeded by atmospheric gases. From what I understand, Kirchoff’s Law applies to electro magnetic radiation in the 10^-1 to 10^2 um which includes “thermal” radiation comprised in part of both infra-red and microwave wavelengths. Observation and simple logic suggest the assumption that MW radiation will pass through the atmosphere unabsorbed seems questionable. BTW neither Joel nor I claimed that “total” and “spectral” emissivity had to be the same or made any comparison between oxygen absorption of MW and a theoretical black body.
Please let me know if I’m missing something. Thanks again for your input.
Interesting.
Some movement towards my position noticed.
No…There has been no movement towards your position.
Joel said:
“The air that gets convected up would cool by adiabatic expansion. Air can’t rise up everywhere without descending in other places, so although there is no natural convective force causing the hot atmosphere to be transported across the cooler ground at night, these sort of subsistence zones might do the trick.”
Nearly there Joel.
You just need to realise that energy cannot be used to both provide radiation and conduction/convection (with associated conversion of KE to PE) simultaneously.
Wouldn’t it be more accurate to say that a body surrounded by a radiating and convecting medium can only lose a given amount of energy through radiation, and any further cooling must be through evaporation or conduction/convection/advection?
It is wrong to say the ground constantly loses 390 W/m^2 and the atmosphere supplies 324 W/m^2 back to the ground.
The ground loses 66 W/m^2 through radiation, the 390 and 324 values only emerge in calculations, they are not represented by physical transfers of energy.
The ground loses a given amount of energy through evaporative and conductive/convective cooling as well, but in this case it is obvious that the ground is not gaining energy from back-evaporation and down-vection, so those values are rightfully only considered as bookkeeping tools.
If I’m paying you 390 dollars for a job and you owe me 324 dollars, you don’t magic 324 dollars into existence, and I assume you don’t demand I give you 390 dollars befroe you can pay off your debt, I give 66 dollars and we’re even, right?
Yet for some reason an exchange of energy which occurs at the speed of light has to pause long enough for a physical realisation of bookkeeping values to take place?
Max.
The numbers I’ve been using for illustrative purposes were provided by Joel, I think.
240 in and 240 out at ToA
150 from surface to atmosphere and 150 from atmosphere in a constant recycling of energy retained long term by the atmosphere.
240 plus 150 gives 390 at the surface.
That 150 is stored as PE not KE and so does not register as heat in the atmosphere but it is constantly being taken from and returned to the surface by conduction and convection so that whereas the surface achieves 390 the atmosphere only actually radiates 240 out to space.
Joel’s conceptual problem is dealing with that 150 because of course it does start as radiation at the surface but it just doesn’t get out to space.
The AGW position is that GHGs absorb it on the way up then return it as downward radiation.
In that event ONLY GHGs cause the greenhouse effect.
I say that the heat of the surface causes conduction and convection so that the surface is potentially cooled but at the same time the descent of air reverses the effect of conduction and conduction thereby negating the cooling effect of that conduction and convection.
That involves the entire mass of the atmosphere so that GHGs at present concentrations become irrelevant anyway.
Thus the surface stays at the same temperature as before but the 150 is prevented from leaving to space.
Note that the conversion of KE to PE and back again happens through the entire vertical column so Joel’s requirement that the surface radiate at 390 is satisfied.
BUT
150 from that 390 never gets to space because conduction and convection throughout the entire vertical column have converted 150 from that 390 of radiation to PE which does not register as heat.
Joel and others just cannot accept that on the way up IR radiation gets converted to PE via conduction and convection. The initial kick start is at the surface but the process continues all the way up.
Radiation in IR form is just Kinetic Energy. KE increases the speed of movement of molecules and that increase in speed of movement causes the molecules to rise higher against gravity and in that process KE (heat) is converted to PE (not heat).
Does anyone dispute that hotter gas molecules rise higher ?
What is the problem for Joel and others in accepting that radiation in IR form heats molecules in the atmosphere causing them to acquire additional energy which is then converted to PE as the molecules rise higher against gravity?
And then to realise that if more KE is present above the surface then the atmospheric heights will increase and the additional KE goes to PE without needing a rise in surface temperature because all the thermal effects involving air molecules are happening above and not at the surface.
There is warming within the atmosphere (assuming GHGs have a net warming effect which is not universally accepted)but not at the surface and total system energy content is not affected.
Instead, just a miniscule circulation change.
You said:
“Yet for some reason an exchange of energy which occurs at the speed of light has to pause long enough for a physical realisation of bookkeeping values to take place?”
Yes indeed.
Radiation in the form of IR (KE) energises molecules
causing them to rise higher and in the process convert KE to PE.
The decline in temperature with height is still present so the top is still colder than the bottom and there will still be convective overturning with descending air getting warmer as PE gets turned back to KE.
So it isn’t simply a bookkeeping exercise.
There really is a real world process whereby IR is converted from KE to PE and back again which does introduce the required pause in the throughput of energy.
The longer it takes for KE to be converted to PE and back again the longer the pause and the higher the surface temperature.
The length of the pause is determined by the amount of mass and the speed and height of the convective overturning and NOT by GHGs.
You’re falling prey to the TOA trick, it’s 480 in*12 hours and 240 out*24 hours.
Trying to operate within the bounds of a nonsense paradigm will do no good.
Only illustrations. The numbers don’t matter.
Stephen,
The plural of nonsense is not science.
That’s clever on a few levels, well done!
It’s amazing that so little seems to be known (at least amongst the knowledgeable on here or easily accessible on the internet) about the radiative characteristics of the two gases which together make up 99% of the atmosphere. I had a good dig about and found that Oxygen radiates at the MW wavelength but incredibly I could find nothing on Nitrogen at all. I found no climate papers on the subject but I may have been looking in the wrong places I guess. All the literature I’ve read just discounts them on the basis that they neither absorb or radiate IR and on that basis they don’t count!
However, everyone seems to agree that they must both radiate at some wavelength and it seems that this wavelength is likely not to conflict with GHG’s. It is also obvious that they gain heat through conduction from the surface and additionally collision with other atmospheric gases. Therefore it seems there is a massive opportunity for these modules to radiate their energy to space once they have acquired it. To me that seems like an open door for heat caught in the atmosphere by GHG’s to be quickly transferred to these modules and then radiated away without interference from GHG’s.
What I am struggling with is how we can say with confidence that the 1% of GHG’s are a problem when the 99% is apparently so poorly understood and have been so easily discounted.
http://i341.photobucket.com/albums/o396/maxarutaru/guest975820037.png
http://i341.photobucket.com/albums/o396/maxarutaru/Selection_032.png
O2 and N2 absorption lines in context with H2O/CO2 (the first image) and by themselves out to 1000~ microns (the second image).
Iansview,
[“What I am struggling with is how we can say with confidence that the 1% of GHG’s are a problem when the 99% is apparently so poorly understood and have been so easily discounted.”]
Me too! (Except I think you meant 99% of the atmosphere, not GHGs – did you?)
Actually, I’d take it further and say: “How can we say with confidence that 0.04% of the atmosphere is a problem when the 99.96% is apparently so poorly understood and has been so easily discounted.” 🙂
Iansview,
You are just grasping at straws. The emission lines have to be somewhere around the far IR in order to be relevant at the temperatures we are talking about. Any emission by N_2 and O_2 in these regions is negligible…Down by many, many orders of magnitude from those of the greenhouse gases.
I understand that you really, really, really don’t want the greenhouse effect to be correct. Unfortunately, science does not operate according to your wishes even if you wish very strongly.
“I understand that you really, really, really don’t want the greenhouse effect to be correct. Unfortunately, science does not operate according to your wishes even if you wish very strongly.”
I do believe there’s a ‘greenhouse’ effect….that is an effect where the radiation leaving the earth has to pass through a mass of gas molecules to a point where it can escape to space, and that this delay in passage of the energy retains it near the earth for an extended period and provides warming it in the process. The difference in our positions is that I don’t see, from a mechanical perspective, how or why, the energy once it has left the surface of the earth could find it’s way back to rewarm it again. This to me defies reason and logic.
“I don’t see, from a mechanical perspective, how or why, the energy once it has left the surface of the earth could find it’s way back to rewarm it again.”
I was referring to back radiation in the statement above as opposed to warming of the surface by energy being distributed from hot to cold regions.
For a handy summary of the radiative characteristics of various gases, look here:
http://www.spectralcalc.com/spectral_browser/db_intensity.php
A plot of CO2, H2O, N2, & O2 should quickly convince you that even the strongest IR absorption bands from N2 & O2 are insignificant compared to CO2 & H2O.
There is little written on the properties of N2 & O2 because they are of such little importance – either theoretically or practically.
(This is the source of the spectra that I jsut noticed that Max had already posted.)
Joel/Tim,
I realise that the N2 & O2 absorption bands are at the bottom end of the spectrum with regard to absorption/emission. However, I also note the quantity of these modules in relation to the quantity of CO2, H2O modules must do a fair degree of balancing up when you look at total energy that they retain. Whilst they will not pick up much of the earths radiation directly they will pick up energy by surface conduction and atmospheric collision and are then more likely to transfer this by collision to another non-GHG module. Just because they don’t pick up a lot of the earths energy from IR directly does not mean they can be omitted from the equation.
Joel STILLdisagrees with you Stephen on almost every count,as do I.
No matter.
It took some time for you to get my point on another issue some time ago.
Iansview
You may be interested in some work of Dr. Jinan Cao on radiative properties of N2, O2 and CO2.
“When CO2 is warmer than its radiative equilibrium temperature, it emits more heat energy than that it absorbs. In other words, CO2 emits not only the heat energy gained from absorption, but also the heat energy gained from N2 and O2 by molecular collisions. A heat transfer route is shown below:
N2 and O2 do not emit heat but pass heat to CO2 by molecular collisions;
CO2 dissipates heat by thermal radiation to space.”
“With this alternative interpretation, we have a better explanation of the temperature-altitude profile in the thermosphere. A CO2 molecule is heavier than N2 and O2 due to higher molecular weight; so is water vapour but due to aggregation of molecular clusters. Neither water vapour nor CO2 reaches the high altitude thermosphere. Even if there are still residual greenhouse gas molecules in the thermosphere, there would be no effective heat transfer by molecular collisions any more because of extremely low air pressure. The temperature in the thermosphere is well above 100°C, increases steadily and exceeds 1000°K with increasing altitude. Without so-called greenhouse gases in the thermosphere, N2 and O2 have no mechanism for heat dissipation.”
http://jinancaoblog.blogspot.com.au/2012/12/carbon-dioxide-radiation-absorber-as.html
“N2 and O2 have no mechanism for heat dissipation.””
No radiative mechanism. They can pass energy to a cooling ground or an evaporating water surface very effectively.
Non GHGs help the surface to dissipate energy by returning KE to the surface in descending air where solar heating is low or absent but immediately regain it in ascending air from solar heating of the surface when such heating is strong enough.
Non GHGs will only retain an amount of KE and PE determined by mass, gravity and insolation so one could say that once the permitted amount of KE and PE is present they will neither absorb nor dissipate energy.
At any given time half of a planet’s atmosphere is descending and half is rising with or without GHGs.
“The temperature in the thermosphere is well above 100°C, increases steadily and exceeds 1000°K with increasing altitude. Without so-called greenhouse gases in the thermosphere, N2 and O2 have no mechanism for heat dissipation.””
The thermosphere radiates very little and so is very much at the mercy of incoming and outgoing energy flows.
Instead of dissipating or absorbing energy it expands and contracts a great deal in accordance with the balance of up and down energy flows.
Mostly it is affected by direct solar input and volume changes are large in response to solar variations.
The lack of contact with a solid surface means that it cannot return energy to a radiating surface in the way the troposphere does.
Stephen Wilde says:
….. N2 and O2 have no mechanism for heat dissipation. ”
Josef Stefan said:
“The whole body heated emits electromagnetic energy ….”
N2 and O2 are spirits or one of you is wrong?
Gustav Kirchhoff said “the equilibrium thermal emissivity and absorptivity of a body are numerically equal.”
To the greenhouse effect is real just a absorptivity of the atmosphere 0.0000692 per meter or 0.0000346 attenuation per meter.
We have fitness for to measure these values??
Us, we will 309 posts, most outside the scope proposed by Dr. Roy and that only goes to show how our science is disconnected from reality. This comes justify the artifice invented by the IPCC to impose the absurd reduction of carbon dioxide to counter global warming called “consensus” that is just a stupid certificate given by climatologists to politicians and lawyers UN.
As the experiment of Dr. Roy, ingeniously created, which shows two equal sets of plates at different temperatures in order to minimize the influence of convective motions in the desired results is that the difference in cooling time of the hot plates.
To understand the result of this experiment we have to understand the postulates of Maxwell, but first we have to know the behavior of packets of electromagnetic energy. The electromagnetic energy to be emitted by a body or an antenna is part of the issuer to a distance of half a wavelength. Surpassing the distance of half wavelength ceases to influence the transmission making it just a package of energy propagating in space. So we can say that any body temperature above zero Kelvin emit thermal energy to be captured by any other body respecting the law of Stefan / Boltzmann. Regardless of the temperature of the bodies
Roy,
The experiment seems like an excellent idea. Your admirable attempt to remove atmospheric convection as an energy transfer medium from the hot plates to the cooler ones by inserting saran wrap between them might work. However, simply performing the experiment in a near vacuum might convince more people. Personally, I find it hard to believe a similar experiment hasn’t been conducted before. Hopefully, the experiment includes controls on other radiation sources including the location and spectral range of lights used for the purpose of observing the experiment. The plate’s possibly varying albedo may also play a role that should be controlled. Perhaps lights can be placed equidistant from all plates, the plates can all have the same color (albedo) and the lights used should all have the same spectral pattern, range, intensity, etc.. No doubt other controls can be applied. Please let us know what you decide to do.
Here’s my view for what it’s worth.
I’ve looked at this from a mechanical viewpoint as that’s where my strengths are. I’m not commenting on the numbers being thrown about other than to say that as a general rule the amount of energy leaving the surface is bound to be the same as the amount of energy leaving the atmosphere to space. I don’t see that back radiation exists as such. I would say back pressure would almost be a better term. Given the reducing density of the atmosphere as it moves towards the tropopause, mechanically IR can do nothing but flow from the surface outwards towards space. That’s not say it doesn’t backtrack on itself a little; in a two steps forward, one step back fashion, but essentially it is flowing one way like a river. However, like a river with a dam across it and a mill pool, the atmosphere is backed up…..that is the energy is pooled in the atmosphere, and whilst it is, the energy is dynamically interchanging between modules all the time waiting for its chance to escape at which ever level of atmosphere and via whichever wavelength it can (I really don’t see that the energy has to leave by any particular wavelength in a bell profile; for a start it isn’t now and that would surely only apply to a object with uniform module composition, not a chaotic one like the atmosphere). Like a river, the fact that the energy is being backed up in the pool does not mean that it is flowing back up from where it came, it means that it is doing the equivalent of circulating in eddies and currents. There is no energy being returned to the surface (redistributed around the surface yes) only a slowing of passage due to the energy already ahead in it’s path.
If it is correct that N2 and O2 cannot do much in terms of radiating their energy to space then the logical conclusion is that they are actually the modules retaining the energy in the atmosphere and by adding more GHG’s the effect, far from being one of warming will be one of cooling as more windows of opportunity arise to dispense with the energy to space.
Right or wrong, that’s how I see it from the information available.
Agreed.
The amount of energy leaving the surface must be the same as the amount leaving the atmosphere for space.
The point being that a portion of the energy that seems to be leaving the surface actually isn’t because it is coming straight back to the surface again.
AGW theory says it is downward IR from GHGs in which case GHGs would be in absolute control as they propose.
I say it is reconversion of PE to KE in descending air in which case it is the entire atmospheric mass which is in control and GHGs become insignificant.
How to choose between the two?
Consider a GHG free atmosphere.
There would still be a temperature decline with height due to the pressure gradient altering density with height resulting in a lapse rate and conversion of KE to PE with height.
With a temperature decline with height there would still be convection.
What goes up must come down so any convection results in an equal amount of descent which converts PE back to KE again.
On that basis it must be mass that creates the greenhouse effect and not GHGs.
Stephen Wilde says:
May 25, 2013 at 11:46 AM
Agreed.
The amount of energy leaving the surface must be the same as the amount leaving the atmosphere for space.
Wrong………
The amount of energy the surface receives from the sun must be the same as the amount leaving the atmosphere for space.
Wrong
Unless one defines ToA as the surface.
It is the energy exchange between the surface and ToA that defines the extent of the greenhouse effect and fixes the amount of energy getting from surface to ToA so as to achieve that balance.
“Consider a GHG free atmosphere.
There would still be a temperature decline with height due to the pressure gradient altering density with height resulting in a lapse rate and conversion of KE to PE with height.”
First of all, whether or not there would be a lapse rate in a GHG-free atmosphere (and I am agnostic in that debate), what we do know for certain is that (assuming a 0.3 albedo) the fourth root of the average of T^4 on the Earth’s surface would be 255 K, not 288 K as it is now. [For simplicity, I am ignoring any small corrections due to emissivity of the surface, which is very close to 1 over most of the Earth at the relevant wavelengths.] This is a simple consequence of the laws of physics that you seem to be incapable of comprehending.
Second of all, you seem to be hooked on Hans Jelbring’s derivation of the adiabatic lapse rate, which suffers from some real problems. One is that if it is done carefully, it doesn’t quite work out: You get a factor of C_V instead of C_P, as I recall. The second is that it doesn’t account for the known thermodynamic effect of gas doing work by expanding.
Admittedly, it was a bit puzzling to me for a while why the traditional derivations of the adiabatic lapse rate did not include an additional gravitational potential energy term in addition to the term for work due to expansion…and I have never seen an explanation of this, but I do think I know the reason: The deal is that one is considering parcels of air that are neutrally-buoyant in the atmosphere and hence that means that the gravitational force on them and the buoyant force on them balance. Hence, the work required to move the gas up and, thus, the change in potential energy due to both of these forces is zero. (It’s like the work that would be required if you wanted to move up a helium balloon that had lost enough of its helium that it was now perfectly neutrally-buoyant in the atmosphere.)
This is a side point, since there are much more serious problems with your whole description that we have tended to focus on, such as the fact that you either have to violate conservation of energy or make up new laws of physics about how much an object radiates when it is also losing heat via convection or conduction, with no justification that they are correct and the laws that have served us well for more than a century are wrong.
But, it is worth point out on just how many levels you seem to be hopelessly confused, some levels admittedly pretty subtle and others blatantly obvious.
Having just been looking back in some of the threads involving the whole “the adiabatic lapse rate is the equilibrium temperature configuration in a gravitational field” fiasco, I am glad to see that Tim Folkerts reached the same conclusion as I did about why there is no net potential energy term associated with moving a gas in hydrostatic equilibrium from one height to another: http://wattsupwiththat.com/2012/01/24/refutation-of-stable-thermal-equilibrium-lapse-rates/#comment-882951
That thread ended with this:
“Because the import of the consequence of the radial temperature gradient created by pressurizing a spherical body of gas by gravity, from the inside only, is that it obviates the need for concern over GHG’s. And, because this is based on long established fundamental principles that were apparently forgotten or never learned by many PhD’s, it is not something that can be left as an acceptable disagreement.”
With which I agree.
It is the pressurizing of a spherical body of gas by gravity from the inside only that makes all the difference.
It was well understood in my youth.
RG Brown’s thread concerned an enclosed vertical container which is wholly irrelevant.
Your quote is simply the last of over 1000 comments, a comment left by BigWaveDave, one of the most clueless posters.
And no, the results there don’t just apply to a closed vertical container. Robert Brown used that just for the sake of illustration. He gave a general argument and there was also talk about papers that had rigorous statistical mechanics arguments showing the equilibrium state was isothermal in a gravitational field.
The amount of denial of science is your position is just amazing.
“Like a river, the fact that the energy is being backed up in the pool does not mean that it is flowing back up from where it came, it means that it is doing the equivalent of circulating in eddies and currents.”
Well, I don’t see any harm in thinking about it in this way. At the macroscopic level, you are correct the net flow of energy is from higher to lower temperature. We know that at the microscopic level, this is due to energy flows going in both directions…but if that freaks you out, there is little harm in sticking to the macroscopic level.
“..and by adding more GHG’s the effect, far from being one of warming will be one of cooling as more windows of opportunity arise to dispense with the energy to space.
Right or wrong, that’s how I see it from the information available.”
Absolutely wrong…And, it is not hard to see that it is wrong. Just look at a spectrum of the radiation from the Earth as seen from space. Where there are strong absorption lines, there is less emission, not more emissions: http://www.geo.cornell.edu/geology/classes/Geo101/101week13_f05.html
And, the reason for this is that good emitters are also good absorbers, so the greenhouse gases are absorbing radiation emitted from the Earth’s surface and lower levels of the atmosphere (where it is warmer) and then emitting it also…but less because it is cooler where this emission that can successfully escape to space occurs.
As you add more greenhouse gases to the atmosphere, the level from which the radiation can successfully escape to space moves higher and higher in the troposphere, to colder and colder levels, where less is emitted (until the atmosphere warms up enough again to restore radiative balance).
Joel,
I look at the data and see different things from you.
http://www.geo.cornell.edu/geology/classes/Geo101/101week13_f05.html
Take the spectra of Earths IR above.
I see a bell profile, based at the 280K level where the IR at the 15-17 & 9 um wavelengths has been displaced to the 10-14 & 8 um wavelengths. E.g. It is the profile of an earth at a temp of 280K where the IR cannot escape neatly due to the atmospheric gases and as a consequence the heat has to hang around a bit and transfer from one form to another before finding a wavelength where it can escape. I note that the graph nearly always used as representative of this emission curve is taken from a tropical setting. It’s no surprise to me then that CO2 and H2O have caused this displacement and that the high surface/near surface temperature in these regions would cause more IR to leave via the ATM window.
Also, another thought on N2 and O2 and their IR/Microwave emission. When these gases are at a temperature of 288K do they not abide by Stephan’s law at emit radiation according to their temperature?
Extending this a bit further, if the earth didn’t have an atmosphere then you could expect a distribution as per Planck’s curve. The effect of the atmosphere (and earths rotation) is to distribute the heat developed in the hottest parts of the earth to colder regions so increasing their temperature above what would be expected otherwise…the heat is thermalised in the atmosphere by GHG’s and transferred by collision to other non-ghg molecules where the heat is effectively trapped as these do not radiate significantly (so everyone seems to believe although I’m not convinced on this point). The warm air is then distributed to a region that would otherwise be much colder (the UK is a good example) where it heats the ground/water (but to a lower temperature than the initial source). The result is less IR going out in the GHG wavelengths and this energy being displaced to the ATM window instead. No back radiation required, simply retention of energy in the atmosphere (as described in my river analogy) and redistribution across the surface by eddies and currents caused by the constant turning over of this energy through conduction and convection.
My feeling is that N2 and O2 must radiate energy according to their temperature like everything else and so this would also explain some of the displacement from GHG wavelengths to the ‘ATM window’ wavelengths.
“No back radiation required, simply retention of energy in the atmosphere (as described in my river analogy) and redistribution across the surface by eddies and currents caused by the constant turning over of this energy through conduction and convection.”
Agreed.
I would just add that it is a constant turning over of the same amount of energy with that amount determined only by mass, gravity and insolation.
GHGs just alter the pattern of eddies and currents and/or the rate of turning over.
Just as would variations in the amount of sediment carried by the water in that river analogy.
Thanks to Roy for letting this run despite it having drifted away from his analogy.
Iansview,
It seems that you are able to come up with convoluted explanations to continue to believe what you want to believe. There is no evidence that there is greater radiation at other wavelengths…and no understood way how there could be. And, we have an entire field of technology, remote sensing, that is based on our correct understanding of radiation transfer in the atmosphere, the same theory that reproduces almost exactly the observed spectra like the ones that I showed you.
But, clearly, you and Stephen are willing to deny all the science necessary to preserve your religious beliefs. I find that quite sad.
Projection.
Roy,
In regards to this topic, I think the following is a simple
qualitative experiment which demonstrates a cooler surface
slowing heat loss from a warmer body. The idea is to
minimize heat loss by evaporation, conduction and
convection. This is the silvered vs. non-silvered vacuum
bottle experiment, but without the vacuum. IT’s easy to do
and requires no calibration, instruments, measurements or
math. Most equipment can be found at hand.
All that’s needed is:
2 clear plastic cups (eg. 10 oz. “Party Tumblers”)
2 plastic tops to fit (eg. from 8 oz. cheese spread
containers)
2 1 1/2 oz. glass jars w/ screw tops (eg. jam samples
that come gift baskets)
OR 2 shot glasses (not as forgiving in handling and
timing)
aluminum foil
piece of thin, stiff cardboard
rough wood toothpicks
refrigerator w/freezer
Using the cardboard, make “X” brackets to fit inside each
cup such that the sample jar will be held off the bottom and
centered in the cup. Line one of the cups and its top with
foil.
Fill each sample jar with water at room temperature to same
level (about half) and put a toothpick in each( to create a
nucleation surface and prevent supercooling.) Screw on
the tops.
Place both cups and tops (w/o sample jars) in freezer to
cool for a bit.
Then remove from freezer, place the sample jars on the
brackets in each cup, put on the respective tops and return
to freezer.
Observe periodically(peek in and tap on shelf) to
determine when water in clear cup has begun to freeze.
When it does, remove both cups and check foil-lined cup
for ice in its sample jar.
Picture of the apparatus: http://i42.tinypic.com/fkbla1.jpg
A result: http://i40.tinypic.com/b3mvqr.jpg
At which point does the water rise above the initial temperature?
What work is being done in this experiment, i.e. what is the source of the gradient which leads to the heat flow from the water outwards into the surroundings?
Repeat the experiment with two glasses of water at room temperature, place them inside the jars but leave the jars in said room temperature room.
Measure the temperature of the water, etc.
Take two glasses of hot water and run the experiment with them cooling to room temperature, measure the time it takes, and see if you can work out in what manner certain components of the atmosphere are supposed to resemble aluminum foil.
Stephen Wilde, your uses of the terms KE and PE show that you have hardly any understanding of transfer of energy in macroscopic systems. You will not make progress till you admit to yourself that in order to understand the present questions, you will need to make serious attempts to study the relevant physical principles. At present you are limited to spin and rhetoric, without physical understanding. So you currently write mostly nonsense.
Please explain what you see as ‘wrong’ in my use of the terms KE and PE.
Dear Stephen, I am not about to try to short-circuit your need to learn the basic physics. I am saying that is something you have to do for yourself.
Just bluster, then.
Arfur Bryant said and repeated (5 days ago):
“There has been no accelerative rise in global temperature since 1998, and it can be reasonably argued that there has been no rise at all.”
Please kindly look at:
“NASA scientists say 2012 was the ninth warmest of any year since 1880, continuing a long-term trend of rising global temperatures. With the exception of 1998, the nine warmest years in the 132-year record all have occurred since 2000, with 2010 and 2005 ranking as the hottest years on record”.
http://www.nasa.gov/topics/earth/features/2012-temps_prt.htm
So, I repeat, that statement was a clear case of misleading CHERRY PICKING.
So where is the ‘accelerative’ rise?
You accept that both 2005 and 2010 were cooler than 1998.
Hi Rafael Molina Navas, Madrid:
Do you suffer from chronic credulity? How exactly did NASA arrive at global temperatures for the period from 1880 through most of the 20th century? NASA and the rest of humanity did not employ satellites capable of measuring global temperatures until 1979. Should we replace empirical scientific investigation and a globally representative measurement sample with speculation. As Mark Twain wrote:
“There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.”
Mark Twain
P.S. – Speculation doesn’t transmogrify into empirical measurement even when “scientists” engage in it.
Rafael,
I have already addresses your accusation of cherry picking earlier in this thread. I will do so again…
Why would you use (a NASA interpretation of) the GISS dataset which starts in 1880 when I have provided the original dataset used by the IPCC which goes back to 1850?
Please do not accuse me of cherry picking when I provide the full dataset available. If I were to select a small portion of a dataset, then you would have a point. I don’t. The full dataset is not cherry picking. Using the entire dataset if available from 1850 to present is certainly not cherry picking.
The HadCRUt3 dataset is here:
http://hadobs.metoffice.com/hadcrut3/diagnostics/global/nh+sh/monthly
A graphical representation (which you did not provide for your GISS data) of the manipulated HadCRUt4 dataset is here:
http://www.climate4you.com/images/HadCRUT4%20MAATand3yrAverage%20Global%20NormalisedFor1979-1988.gif
I urge you to look at this graph and point out where the ‘acceleration’ is in the 0.8C warming since 1850.
You will note that a straight line drawn from the origin of the graph to each successive peak along the x-axis has its steepest value at 1877. Now I ask you, if the line is steeper to 1877 than it is to 2013, how can the warming be accelerating?
I also ask you to note that the GISS dataset conveniently misses the peak at 1877. Even so the GISS dataset provided here…
http://data.giss.nasa.gov/gistemp/tabledata/GLB.Ts+dSST.txt
…still does not indicate an acceleration!
I keep asking people to be objective in this debate.
John K makes a good point. I have provided you with the facts (or as close as it gets to ‘fact’ in the climate debate) as measured by observation since 1850. Do not be swayed by an ‘appeal to authority’ argument based on assumption. Look at the facts and make your won judgement.
Providing the entire dataset is NOT cherry picking!
There is no overall acceleration.
The fourth word should read ‘addressed’.
I wish there was an edit button… 🙂
Words, words … words.
The statement of yours mentioned by me was about temperatures since 1998 …
To speak now about 1850 and 1880 … is not to have better arguments.
I could also say: “The global mean temperature anomaly average in the period 2000-2012 is 0.13ºC higher than in 1989 …” (!!!)
THAT would be cherry picking too, because I´d be comparing with a year clearly colder than the average …
Rafael,
My first comment was this: “There has been no accelerative rise in global temperature since 1998, and it can be reasonably argued that there has been no rise at all.”
I have provided you with DATA that shows there is no acceleration in the warming since ‘accurate data’ began in 1850. You then chose to use 1880 as a start date for some unknown reason. My initial statement stands. Where is the acceleration? Any acceleration that existed between 1975 and 1998 stopped in 1998. Using a short, interim portion of a dataset (such as 1975-1998) would certainly be cherry-picking. Providing you with the entire dataset merely emphasises the veracity of my original statement.
There is CERTAINLY no acceleration since 1998, so why are you even questioning this? If you disagree, please provide evidence. Just exactly where do you think I have cherry-picked?
Why 1998? Remember, 1998 was the year selected to ‘sell’ the cAGW scare to the unsuspecting world public with the production of the MBH98 graph. Since 1998, there has been either no warming or no acceleration. How much more of an indictment against such pseudo-scientific claptrap do you require?
It is not “words, words, words…”, it is “data, data, data…”
As for your NASA 400ppm link below, I URGE YOU TO THINK FOR YOURSELF! Those people are beyond redemption if they really mean what they say. It is unashamed advocacy and/or dogma and has nothing to do with the scientific method.
Be objective.
And regarding CO2, please kindly see:
http://climate.nasa.gov/400ppmquotes/
But if you are more prepared and have better information than all those NASA scientists … I have nothing more to say.
Oh!
My God!
Well stated.
Rafael Molina Navas, Madrid,
You wrote:
“But if you are more prepared and have better information than all those NASA scientists … I have nothing more to say.”
Actually, after perusing a few of the hyperbolic, alarmist sentiments and opinions expressed by these supposed NASA scientists I can only conclude that many three your olds possess more acute scientific reasoning skills than some of these clueless academic propagandists. The only empirical fact I recall them mentioning related to the 400 ppm CO2 measurement which seemingly sent most of them into paroxysms of simplistic, alarmist babble. More than one claimed to know CO2 levels millions of years ago without providing any empirical evidence. Of course, how can one provide empirical evidence or make any meaningful claims about events and time periods know one ever witnessed? The very fact that some will engage in such chimerical nonsense provides more than ample reason for any honest organization to remove them from research projects (unless, perhaps they acquire the ability to be objective or the organization actually approves of such methods to arrive at dubious ends) as one will never know to what extent the information provided bears any relation to observation.
Of course, after saying all that I understand the next big space project involves selling seats on a space ship destined for a one-way trip to land on Mars. Apparently, Mars will be turned into a giant planetary mortuary for billionaires! Supposedly, this will advance science somehow. Or maybe it will only advance the financial ambitions of professional academics who may have little to offer the market place but found a ready cash-stream from the U.S. Federal Government. Perhaps the 2nd Law of thermodynamics has an analogy in politics. In any closed government agency the amount of energy and drive unavailable for useful projects must always increase to fund useless projects of little or no relevance. Follow the money.
To everyone,
The 2nd Law as applied to politics might better read:
“In any closed minded (hence closed to outlside information, concepts or ideas) government agency the amount of energy and drive unavailable for useful projects must always increase to fund useless projects of little or no relevance.”
Roy, you are really describing two copies of the same experiment, one with the cool plate at 0 F and the other with the cool plate at 80 F. If the two plates are situated fairly close together we can assume a view factor of near unity. In any case the geometry will be such that we can ignore view factors. You have also by use of saran wrap attempted to minimize and ignore effects of convection and heat diffusion through the air molecules traveling between the plates, so the “thought” problem is entirely radiative.
The energy per unit time emitted by the plate at absolute (deg K) temperature T1 is proportional to T1**4 and impinges on plate 2 where it is absorbed, however plate 2 at temperature T2 is also emitting energy (in the form of photons) proportional to T2**4 which is absorbed by plate 1.
If plate 2 is the cooler plate, it emits at a rate less than plate 1, and receives more from plate 1 than it emits.
So both plates will eventually equalize their temperatures over time as (net) energy transfers from the hotter to the colder until the net rate of energy transfer between becomes zero and no more change occurs. Until that happens the net rate of energy transfer will be proportional to ( T1**4 – T2**4 ) ( the difference of the fourth power of the absolute temperature (deg K)). So if the difference is greater like in the case of the cooler plate at 0 degrees F versus 150 deg F, the net rate energy transfer will be greater, and the hotter plate will cool more quickly than the case where the cool plate is at 80 F.
Even when the plates are the same temperature, energy will be transferred in both directions but statistically, the net rate of transfer will be zero.
Perhaps the next step would be to adjust the model to mimic some basic features of the atmosphere?
Alan and Roy,
The question posed by this experiment remains what Roy claimed it to be:
“My question is this: Will the two hot plates cool at different rates? I predict the heated plate exposed to the ambient (80 deg. F) plate will consistently stay warmer than the other heated plate exposed to the chilled (0 deg. F) plate.”
The answer must undoubtedly be yes, the two hot plates will cool at different rates. However, because of the possibly fickle nature of convection/conduction I still claim the experiment would be better performed in a near vacuum to eliminate the effect as much as possible rather than to try and explain it away later.
Have a great day!
Joel said:
“As you add more greenhouse gases to the atmosphere, the level from which the radiation can successfully escape to space moves higher and higher in the troposphere, to colder and colder levels, where less is emitted (until the atmosphere warms up enough again to restore radiative balance).”
If the average level from which radiation can escape rises higher that can only be because the GHGs and other gases (which receive energy from the GHGs by conduction) rise higher against the force of gravity.
That additional rise in height converts more of the kinetic energy held by those molecules to potential energy which is a cooling effect.
So no change in the rate of outgoing radiation and no need for a rise in surface temperature. Just a change in air circulation to accommodate the expanded atmosphere.
AGW theory seems to rely on GHG molecules absorbing more kinetic energy but then remaining at the same height as before.
We all know that the more kinetic energy carried by a gas the higher from the surface it will rise so how are they able to deny the well known thermal consequences of such a rise?
At the surface the energy content of a gas molecule is all KE whereas at ToA it is near 100% PE.
The proportion of KE to PE is graded as one goes up by the pressure and density change induced by the gravitational field.
PE does not register as heat, hence the decline in temperature with height.
That decline in temperature with height is nothing to do with radiative loss to space so those who say that the cold at higher levels is due to radiative loss from GHGs are wrong.
The truth is that molecules at the surface and molecules at ToA have exactly the same energy content. All that changes is the relative proportions of KE and PE.
Radiative physics tells us nothing at all about the vertical temperature profile of an atmosphere. It is all about non-radiative mechanical processes within a gravitational field and therein lies the AGW error.
Hi Stephen,
for what it’s worth, I agree with you about KE & PE.
Because I can’t imagine a TOA outermost layer if it’s true that the temperature in gases is their KE.
That is how could exist a layer having no vertical KE but all tangent KE, if that same KE come from the layers below?
“If the average level from which radiation can escape rises higher that can only be because the GHGs and other gases (which receive energy from the GHGs by conduction) rise higher against the force of gravity.”
No.
Adding more CO2 can raise the level from which radiation escapes independent of bulk motion of the gases to higher altitudes. Increasing the CO2 concentration from 300 ppm to 400 ppm does not significantly raise the center of mass of the atmosphere. But level from which the IR escapes to space WILL be significantly higher.
The issue is attenuation, not center of mass.
(you could even remove an equal mass or # of moles of N2 as you added the CO2 and the “effective radiating level” would still get higher, even with the center of mass staying exactly constant. Of course, this would result in the atmosphere warming up, which in turn would make it rise. But here is is very clear that any expansion is a RESULT of the TOA rising, not a CAUSE of the TOA rising)
The increase in mass from a rise in CO2 concentration from 300ppm to 400ppm would obviously not significantly raise the centre of mass of the atmosphere.
However the GHGs themselves would rise higher (as would non GHGs that receive energy from them via conduction) and since radiative gases do nearly all of the radiating from the atmosphere it must follow that the level from which IR escapes to space from the atmosphere will be significantly higher as you say.
But you cannot increase radiation from the atmosphere without also reducing radiation from the surface otherwise ToA outgoing will be out of balance with ToA incoming.
So GHGs acquire more energy and rise which causes a miniscule amount of expansion and more radiation from atmosphere to ToA and then the circulation slows down within the atmosphere to cause reduced radiation from the surface thus keeping ToA in radiative balance.
The circulation will always change speed to negate the thermal effects of GHGs by varying the amount of energy delivered back to the surface for radiation from surface upwards.
That is what keeps ToA in radiative balance whatever the composition of the atmosphere.
It really does work out that way Tim but it needs a leap of imagination to see it and I think it is an understanding of meteorology that breaks the conceptual block rather than understanding of physics.
AGW proponents tell me to go away and learn the physics that they rely on. I tell them that if they go away and study meteorology they will come to my conclusion.
Far too few atmospheric physicists know anything about meteorology and that is why professional meteorologists tend to disagree with AGW theory.
“But you cannot increase radiation from the atmosphere without also reducing radiation from the surface otherwise ToA outgoing will be out of balance with ToA incoming.”
You got that completely backwards!
By raising the “ToA”, you will REDUCE the radiation to space because it is coming from a colder place (as guaranteed by the higher altitude and the lapse rate). These new, higher, colder CO2 molecules will block the “warmer, brighter” thermal IR from below and emit their own “cooler, dimmer” IR.
Uhmmm… So the captured photon is “warmer” and “brighter”, while the re-emitted one is “cooler” and “dimmer”…
But it wasn’t always said that any object didn’t matter of the origin of the photon? That is, it doesn’t matter what it was the temperature of the body which emitted it.
On one side cooler bodies warm warmer ones, on the other side don’t they do it?
Energy in – energy out shouldn’t it be a “must” for the thermal equilibrium of the molecules?
So, how could a CO2 molecule capture a “warmer” photon and re-emit a “cooler” one?
IMHO any molecule (into an averaged thermal equilibrium) capture a certain quantity of energy and re-emit the very same quantity. The temperature of the molecule define just how much it is that quantity.
Please tell me where I’m wrong here.
Have a nice day.
Massimo
I think you have it backwards.
A higher atmosphere reduces density throughout the column and allows energy out faster not slower.
If it were as you say then expanding an atmosphere heats the surface.
So, if one weakens the gravitational field allowing the atmosphere to rise higher the surface gets hotter?
I don’t think so.
A weaker gravitational field allows a higher more diffuse and less dense atmosphere which gives a colder surface not a hotter one.
Suppose the atmosphere where to be so diffuse as to extend from Earth to Neptune.
Would you say the surface would be hotter or colder ?
You are trying to tell us that it would be hotter.
The less dense and more diffuse (and higher) an atmosphere becomes the weaker the greenhouse effect and the colder the surface until eventually the atmosphere dissipates and the surface becomes as cold as space.
It cannot be otherwise.
On the other hand if one reduces the height of an atmosphere it gets denser and denser and the surface gets hotter. Eventually the atmosphere could compress or congeal to a solid and then when irradiation is added one gets the highest temperatures or when irradiation is not available the surface becomes as cold as space.
It is the gaseous nature of an atmosphere that mitigates both heat and cold. That mitigation of both hot and cold is the greenhouse effect. It is a product of mass and is subject to the Gas Laws rather than radiative physics.
Hi Tim,
You wrote:
“Increasing the CO2 concentration from 300 ppm to 400 ppm does not significantly raise the center of mass of the atmosphere. But level from which the IR escapes to space WILL be significantly higher…..you could even remove an equal mass or # of moles of N2 as you added the CO2 and the “effective radiating level” would still get higher, even with the center of mass staying exactly constant. Of course, this would result in the atmosphere warming up, which in turn would make it rise. But here is is very clear that any expansion is a RESULT of the TOA rising, not a CAUSE of the TOA rising.”
Since CO2 concentrations rose from ~350 ppm (1958) to 400 ppm (current), what measured increase in TOA (I assume you mean “top of atmosphere”)if any occurred during the same time period? What definition of TOA did those measuring it use? Who did the measurements? What methodology did they apply? Thanks for any information you can provide.
Hmmm, I find it hard to argue with Joe’s points about the mathematics involved in these discussions.
That does not surprise me in the least. 😉
So you agree that his point regarding the way Roy and others (Willis most egregiously) pull the “internally heated body with constant power” means they’re taking the Q=(T_hot^4 – T_cold^4) equation and declaring that Q is no longer a dependent variable?
Max,
The only person who that argument would be at all convincing to is someone who has never done a problem involving the steady-state temperature of an object. Since Tim and I have, we find the argument to be pretty humorous in a sad, kind of pathetic, way. The fact that you find it especially compelling is really, really sad!
I’ve done lots of math too, whoopdeedoo, do you have a better reason why mixing independent and dependent variables isn’t something which should be declared clearly than “ha ha, you’re dumb”, or is that the limit of your argumentative ability there, champ?
So Max, are you REALLY claiming that the incoming sunlight DEPENDS on the temperature of the earth? The earth DOES absorb (on average) 240 W/m^2 of sunlight = a constant power. This is independent of the temperature of the surface or the atmosphere. So yes, the solar input IS an “independent variable” in this case.
The temperatures of the land and atmosphere adjust until they are emitting 240 W/m^2 to space. The temperatures are the “dependent” variables in this case.
*******************************************
Other than perhaps “time”, there are no variables that are unioversally “dependent” or independent. For example, in the equation
(Density) = (mass) / (volume)
which is the independent variable, which is the dependent variable, and which is the proportionality constant? The answer is that any of the three quantities could fulfill any of the three roles depending on the situation.
Density is intensive, mass and volume are extensive.
Mass and volume can be added and subtracted by simply counting components, density is a property of the components themselves, ten nickels are not more dense than five nickels, are they?
As for your laughable comment about averaged input being the same as a constant input… do you know what thermodynamics is, and how it is more or less the study of gradients which your choice of averaging method eliminates?
Hell, do you know what that equation I listed meant?
T_h^4 – T_c^4 is just a way of saying: “colder bodies are warmed more effectively by hotter bodies”, so yes, the temperature of the planet at a given location determines how rapidly it is warmed by sunlight, I don’t know how you got the “incoming sunlight DEPENDS on the temperature of the earth” nonsense from anything I’ve said though.
The heating ability of that sunlight depends on the temperature of the earth, without a gradient there would be no heating at all, this is what thermodynamics covers, did you not know this?
Max, once again you miss the point. No variable is intrinsically “dependent” or “independent” in an equation. (Which is completely different from your intrinsic/extrinsic answer.)
In this particular discussion, if we have your postulated “internally heated body with constant power”, then yes, the energy flow from the heater to the “body” will be a constant — pretty much by definition.
I would say more, but I suspect we are already too much at cross-purposes. I “get” what you are trying to say, but further progress would probably require us to sit down sop that we don’t keep talking past each other.
If you write Q=(T_h^4 – T_c^4) you’re probably looking for the value of Q which results from the known temperatures.
If you already know the temperatures and yet declare Q is fixed, what are you solving for?
The whole point is that you don’t know the temperatures: The temperature of the Earth (and atmosphere) adjust so that the Earth emits as much back out into space as it absorbs from the sun. It is a fiction invented by the Slayers that a certain important of the sun is associated with a certain temperature. They do that calculation by simply setting T_c = 0 (with no justification).
Postma is a con man…and you are being conned.
“important of the sun” should be “input from the sun”
By the way, despite what Postma says, you don’t need to consider the time-dependence of the insolation in order to get the radiative balance right, as long, as you are only interested in average quantities for the temperature, specifically the average of T^4 over the surface.
However, if you do want to understand the time-dependence, Postma is certainly not the first person to do it. Arthur Smith, a colleague from grad school, has a nice presentation here: http://arxiv.org/abs/0802.4324 The big advantage of his over Postma’s is that he actually does it in a way that gets the total energy received by the Earth from the sun correct.
The total energy from the Sun absorbed and emitted by the Earth is 1.22×10^17 Joules per second.
But the Earth emits half of that on the day side as it is receiving energy and half on the night side.
We know the temperature field for various locations, but there is no such thing as an “average” temperature for the planet, that is a nonsense statistic.
(1) Arthur considers the full time-dependence so you complaint about averages is irrelevant to my post.
(2) That being said, the way one defines an average of something is to sum the values and divide by the number summed. If you have a continuous array of values, such as on the surface of the Earth, the sums becomes integrals.
(3) If you are freaked up by averages, then you can just do the calculation by looking at total energy in and out. You get the same result. Again, Postma is just engaging in sophistry. You have been conned.
“I predict the heated plate exposed to the ambient (80 deg. F) plate will consistently stay warmer than the other heated plate exposed to the chilled (0 deg. F) plate.”
I agree with you, Roy.
There is more heat transfer with the heated plate exposed to the chilled plate. Heat flows from hotter to colder systems (it’s the entropy, folks).
Regards.
You might find this paper helpful!
http://www.ingentaconnect.com/content/els/00179310/1999/00000042/00000023/art00093
I think the model is inconclusive for radiation.
If you have two plates opposing each other and you heat one, you instantaneously heat “the surface” of the other. Such is the inherent nature of surfaces.
If the heat capacity of the cooler plate is zero the time to equal surface temperature is zero.
Since there is no heat capacity worth considering in a single molecule thick surface the warming time is instantaneous and the two surfaces take on an identical temperature.
Ignoring the importance of the thickness of insulation and the heat capacity of the rooms you want to warm or cool is a recipe for failure in the heating and air conditioning business.
With zero thickness and zero heat capacity, 2 dimensional surfaces are like lines they have no substance, so heating is instantaneous.
And here is the kicker being instantaneous disallows a greenhouse effect.
Thats because “watts” is a time dependent notion.
No delay in reradiation no ability to back up heat. Double glaze glass is conductive enough its not considered to be an insulator. But it does set up two heat gradients, one in each pane.
My understanding is its difficult to establish heat gradients in gases without something like gravity to create a pressure gradient.
Thus the experiment you provide above would actually measure something else than an effect purely from radiation. . . .namely the rate of conduction through the cooler plates and their heat capacity. . . .even though radiation is transferring heat on demand.
Having done some heating and air and passive solar design work I recognized this argument in the paper by Gerhard Gerlich and Ralf D. Tscheuschner, 2007. It prompted me to read the reply of an effort sponsored by Real Climate. I was really disappointed that the reply wasn’t quantitative and rested entirely on subjective opinions and thought experiments.
So while the experiment can be convincing to many, so are a lot of magic tricks. . . .our perceptions are easily deceived.
(1) As one of the authors on the reply to G&T, I can say that there is no connection that I know of to RealClimate, other than the fact that most of us probably read (and comment at) RealClimate.
(2) It is strange that you claim that “the reply wasn’t quantitative and rested entirely on subjective opinions”. That is an excellent description of G&T’s paper itself. Our reply in fact had lots of quantitative stuff including the quantitative calculations for a simple model of the greenhouse effect where it was possible to show explicitly that the 2nd Law wasn’t violated even though the presence of the atmosphere caused the Earth’s surface to be warmer than in its absence.
Some very good points from Bill.
Heat capacity and conduction/convection are all non radiative processes and it is they that delay the transmission of radiative solar energy through a planet and its atmosphere.
The greenhouse effect arises when free radiative energy flow is constrained by non radiative processes.
The radiative characteristics of constituent molecules do not in themselves increase the delay in energy throughput.
In order to cause any additional delay the radiation from GHGs has to engage in a further interaction with the mass of the planet or atmosphere so as to further increase the ability of the planet and atmosphere to retain energy.
I haven’t seen any evidence that radiation from GHGs can increase the delay in energy throughput beyond that already set by mass and gravity.
Sure they can send radiation off in directions other than straight out to space but that is only a redistribution of existing energy that will be compensated for elsewhere in the system by rearranging local or regional energy flows.
It is not sufficient to simply say that any energy sent in a downward direction necessarily heats up the system as a whole.
What is the evidence that GHGs actually increase the capacity of the available mass to obstruct solar throughput overall?
“What is the evidence that GHGs actually increase the capacity of the available mass to obstruct solar throughput overall?”
We’ve explained the evidence again and again: The Earth is at a temperature where it is emitting ~390 W/m^2 of ***RADIATION***. And, yet the Earth as seen from space is emitting only 240 W/m^2. The only way radiation can disappear is if it gets absorbed by elements of the atmosphere capable of absorbing electromagnetic radiation. This cannot be explained away by writing nonsense sentences that you randomly put a lot of science-y sounding words in.
Furthermore, the spectrum seen from space corresponds exactly with the spectrum calculated using the known physics of radiative transfer.
Joel,
Saying that Earth’s surface radiates ~390 W/m^2 while the top of the atmosphere radiates 240 W/m^2 is just another way of saying that the Earth’s surface is warmer than the cloud tops. We get it.
You can’t hope to explain the “Greenhouse Effect” using Arrhenius or “Radiative Transfer”. You need thermodynamics:
http://www.youtube.com/watch?v=VnbiVw_1FNs
The thermodynamics is included in the modeling of the greenhouse effect that goes beyond considering purely radiative effects to including convection (& evaporation / condensation, etc).
Simple models are kept simple to show the basic physics. More complicated models are used to get the quantitative stuff right.
“The greenhouse effect arises when free radiative energy flow is constrained by non radiative processes.”
“In order to cause any additional delay the radiation from GHGs has to engage in a further interaction with the mass of the planet or atmosphere so as to further increase the ability of the planet and atmosphere to retain energy.”
“I haven’t seen any evidence that radiation from GHGs can increase the delay in energy throughput beyond that already set by mass and gravity.”
These sentences are just a bunch of nonsense gobbly-gook with nothing to back them up. When real scientists write sentences describing things, they have equations and calculations to back them up. You just have meaningless drivel with nothing to back it up.
Seems clear enough to me.
Thanks for pointing that out Joel.
We must always remember the rock solid climate sensitivity numbers, model predictions (oops, sorry) I mean scenarios, and how recent temperatures make all this arguing over climate science a foregone conclusion. Now where’s that Kool-Aid stand again? You look thirsty and I’m not sure the first helping had it’s intended effect on you.
Your post is irrelevant to the issue at hand. Just because there is uncertainty about climate sensitivity, it does not follow that we don’t understand the basic physics of the greenhouse effect.
And how is your “understanding” any better than Stephen’s? What amazing revelations have come from it? What explanatory power does it have?
It explains the elevated temperature at the Earth’s surface and at the surface of Venus without having to make up your own laws of physics.
And it’s just a coincidence that Earth and Venus have essentially the same temp given their distances from the sun right? Color me unimpressed.
Some people are not impressed by science…They prefer ignorance. You appear to be one of them.
Some prefer to use the word science as a shield to protect an inadequate idea rather than as a method for uncovering the truth.
Stephen, unlike Dr. Spencer who has dementstrated through experimentation /data that the GHG effect is real, you fail to show us any proof to the contrary other then what you say.
Show us through experimentation or data that what you claim is true.
Your thoughts can’t explain anything when it comes to how the climate system of the earth works and how it works.
I have said the GHG effect is limited due to the energy it has to work with in the earth /climate system.
Stephen again if the the composition of the atmosphere on two given planets is different and everything else is the same, you are not going to have the same lapse rates , or temperature profiles of the atmosphere and thus weather, and climate, it is NOT going to take place.
If you think this is not so, then you don’t know what you are talkng about, to put it bluntly.
But that is exactly what I do say.
The composition difference tries to drive different lapse rates and temperature profiles but that would, if uncorrected, force a ToA radiative imbalance.
So the circulation changes instead in order to correct the potential imbalance and of course the weather and climate will be different.
But the greenhouse effect (which is obviously real) is caused by total atmospheric mass so the effect on circulation from our CO2 emissions would be so small as to be unmeasurable.
I am at a loss as to how my words are just not sinking in.
Again if you have two planets with everything the same other then atmospheric composition, the lapse rates, the surface temp./atmospheric temp. profiles, and thus the weather and climate are NOT going to be the same, for those two planets,regardless if the energy coming from the sun is the same for each of the two planets.
If anyone thinks otherwise, they don’t know what they are talkng about.
I would expect two planets with different atmosphere compositions to be different.
Dr. Spencer in another thread says the atmosphere in the absence of emissivity would trend towards isothermic. I agree. But I don’t agree that the isothermic temperature would be that of the average temperature of the surface. I think passive solar heating technology proves that to be false.
Heat is trapped in the convective loops of a greenhouse, the greenhouse only cools by conductivity through the glass. An atmosphere effectively has a cap that has zero conductivity to space so its a very hot greenhouse relative to what we can build. I think via this you can make a case that says
1) Greenhouse gases with their poor emissivity relative to the surface will cause the atmosphere to warm above the average temperature of the surface (with no atmosphere)
2) non-greenhouse gasses with even worse emissivity will cause the atmosphere to be even hotter than the greenhouse gas atmosphere (on average).
3) In the absence of weather, conductivity of heat from the Stevenson screen level (estimated at 1.5m elev) to the radiating surface is negligible. Therefore a large diffence could exist. . . .between the readings of our instruments and the average temperature of the surface.
4) The extra emissivity of a greenhouse gas atmosphere over a non greenhouse gas atmosphere would serve to close the difference between the radiating surface and the atmosphere (and by extension the Stevenson screens)by warming the surface (even if only when the surface is colder than the atmosphere) and by cooling the atmosphere which I think is a fact.
Hi Bill,
“Dr. Spencer in another thread says the atmosphere in the absence of emissivity would trend towards isothermic. I agree.”
I would like to know:
how do you explain in an isothermal atmosphere the very outer layer behavior?
I mean, I would like to know if there is any explanation on how a gas (which its temperature is the KE) could acquire only horizontal motion without any vertical one (it’s the very outer layer there, so the molecule can’t rise higher). Especially if you consider that its only source of KE are the underlying layers.
In few words: how could be that in a GHGs less isothetmal atmosphere the molecules don’t escape to the outer space?
I know that Maxwell said that if there was a lapse rate without GHGs, placing a thermal conductive column between the surface and the TOA, there was a perpetual machine but I think that he committed the very same mistake of considering the Kirchhoff law valid when the system is submitted to an energy flux.
That is the isothermal atmosphere could exist without the Sun radiation, when the Earth finally falls down to the very few K of the outer space.
IMHO, placing the thermal conductive column from the surface to the TOA, there is no perpetual motion. It’s just the same of having the GHGs: the TOA could warm a little, but it doesn’t because the solid column should behave as a radiator there which possibly starts a convective process to the surroundings gases (I write “solid column” because it’s the only one which could express a different gradient as function of the altitude respect to gases; otherwise for me it’s unexplainable why the average mixture of N2 and O2 on the whole atmosphere remain the same).
I know, maybe I’m wrong but I would like to know where I’m wrong.
Have a nice day
Massimo
“I mean, I would like to know if there is any explanation on how a gas (which its temperature is the KE) could acquire only horizontal motion without any vertical one (it’s the very outer layer there, so the molecule can’t rise higher). Especially if you consider that its only source of KE are the underlying layers.”
If you pour some warm liquid into a corner of a glass the warm liquid will spread across the surface of the glass using gravity. So its not clear to me what you are getting at. As Roy says when an atmosphere becomes isothermal weather stops because convection stops, so it would seem both horizontal and vertical motion would stop.
Convection in a variable solar world would not stop completely but it seems there would be a strong propensity to little convection being required to warm the bottom most layer of the atmosphere after a night of cooling.
Sorry for my English, I’m Italian and I know that I have some problem with it.
What I mean is: how do you think the molecules of an isothermal atmosphere can reach the outer layer at the TOA?
AFIK gases molecules are thrown away from the surface by thermal excitation, they should rise at a certain altitude when their thermal acquired KE is fully converted to PE by the gravitational field of the planet and then they should start to fall down.
Of course mine above it’s an oversimplification, since the KE can be acquired and shared from/with the underlying molecules, but IMHO the overall behaviour should be that.
And since more the altitude is higher more the averaged KE is converted to PE, and the KE should be the temperature for gases, I guess that an isothermal atmosphere shouldn’t exist.
To exist, the molecules at the the TOA very outer layer should have a full horizontal KE otherwise they weren’t at the TOA.
Maybe I’m saying silly things, because I’m just an electronic engineer, but I would like to know where I’m wrong.
Have a nice day
Massimo
Ok I think I understand better. The answer is the atmosphere need not convect to warm. Heat is also transferred by conduction. Its a far slower process that never accumulates with greenhouse gases in the atmosphere radiating heat off faster than the conduction operates.
I agree, but my question is:
since even in the hypothetical isothermal atmosphere the gases molecules are displaced up to the TOA, how could they reach that place and remaining there if there wasn’t a vertical KE which finally was whole converted to PE? (otherwise the molecules should never stop and should escape into the outer space).
Well since the KE is the temperature in gases, I see two possibility here:
1) there is some physical law which converts the vertical KE into a perfectly horizontal one at the TOA, because only this way the temperature will be the same at the surface and the TOA and the molecules stop to rise at the TOA (but till today I failed to find that law)
2) KE is progressively converted to PE as the molecules rise or transfer their energy to the upper ones, so the isothermal atmosphere doesn’t exist at all;
Note that in case 2, even if there was (as I believe) a gravitational induced lapse rate, the average number of molecules which cross any single horizontal layer upward and downward will be the same anyways.
In fact, the supporters of the isothermal atmosphere argue that it can’t be possible to have a gravitational induced lapse rate because at equilibrium the same number molecules must cross any single horizontal layer upwards and downwards. But IMHO they are wrong, because even in the gravitational lapse rate atmosphere the average crossing speed of any horizontal plane is the same. The difference is that the upward molecules are decelerating 1G while the downward are accelerating 1G, but at thermal equilibrium they have the very same speed which is different for any horizontal layer (I’m always talking about average speeds of course).
Hope I’ve been clearer.
What do you think about this?
Here is 1:35 AM, now I go to sleep.
Have a very nice day.
Massimo
Massimo, maybe it would help to consider for a moment an atmosphere with so few molecules that we can ignore collisions.
Every time a molecule hits the surface (assumes to have a uniform temperature), it will get some randomized amount of thermal energy — sometimes it will go fast and sometimes it will go slower (ie the Boltzmann distribution). If we look right near the surface, we will “see” the all the molecules every time and we can use the average KE to find the temperature near the surface.
Now go up higher and find the average KE. Something interesting happens. The particles that started with a low KE never even reach this higher level, so they never get counted. Only the particles that started with above-average KE reach this level. Of course, they lost some of that initial KE on the way up. The net result is that the few particles that DO reach this level STILL have the same average KE as greater number of particles near the surface.
Increasing the density doesn’t change this basic result. The self-selected particles with enough energy to get to the higher altitudes will lose exactly enough KE to maintain a constant temperature (at the expense of decreasing pressure and density)
Massimo, you are still talking about a convecting atmosphere or seem to be confounding convection with the natural movement of gas molecules.
It also seems you are confounding the motion of gas molecules because of their KE with the instability of a column of gas caused by unequal warming and cooling that results in convection.
Hi Tim,
I agree with your explanation of the distribution of the molecules, but if the KE is the temperature in gases that doesn’t means that the temperature falls along the altitude?
IMHO you are wrong when you believe (or at least I understood that you believe) that the molecules which reached a certain altitude because of their initial KE, still posses that initial KE
In fact, your assertion that the molecule having more KE reaches that higher altitude doesn’t means that at the maximum altitude that they reach, they still have that KE. That’s the altitude where they fully converted their initial KE into PE indeed.
If it was as like you suggest (or I misinterpreted) the gases molecules are the only bodies which didn’t convert their mass and ascensional speed into PE.
Have a nice day.
Massimo
Hi Bill,
“Massimo, you are still talking about a convecting atmosphere or seem to be confounding convection with the natural movement of gas molecules.
It also seems you are confounding the motion of gas molecules because of their KE with the instability of a column of gas caused by unequal warming and cooling that results in convection.”
No Bill,
sorry I should explain it in may last post but I missed to do it :(.
I never talked about convection or bulk movements of air, which I fully agree that must disappear into a non GHGs atmosphere. I always talked about molecular speeds, the bulk air movement in the hypothesized missing GHGs atmosphere should be very low and due to diffusion.
But “isothermal” means for me that all the molecules have the same mass*speed product (KE) at any altitude, no matter if their average speed in any direction is zero. Any single molecule should have the very same KE (that is speed*mass or temperature for gases) at any altitude.
IMHO that is impossible. That’s Because if it was true they were the only bodies which didn’t convert KE into PE moving away from the gravitational field.
In fact, if it was true they should never stop at all their rising to the TOA, while they do (at the TOA of course).
IMHO the simple fact that the molecules stop to rise and start to fall at the TOA, should imply that the atmosphere can’t be isothermal at all. It should have a lapse rate imposed by the gravitational field.
Have a nice day.
Massimo
By the way,
in my last post I wrote KE = speed*mass just to simplify the concept.
It’s (mass*speed^2)/2 of course.
Massimo
Massimo says: “IMHO you are wrong when you believe (or at least I understood that you believe) that the molecules which reached a certain altitude because of their initial KE, still posses that initial KE”
That is not quite what I meant. The DISTRIBUTION of KE will be the same at different altitudes. This is subtle but critical.
Consider a set of particle with thermal energies as listed below. 100 Particles have ~ 0 units of KE. 90 particles have 0.1 units of KE … (The number of particles drops off exponentially)
ENERGY # of Particles
0 100
0.1 90
0.2 81
0.3 74
0.4 67
0.5 60
…
4 1
4.1 1
4.2 1
4.3 1
4.4 1
The 1020 particles I checked had an average energy is 0.877 units of energy.
Now let these particle rise so that they have lost 0.1 units of KE. The 100 particles with ~ 0 units of energy don’t make it that high. The next 90 particles now have about 0.1-0.1 units of energy = 0, the next 81 particles have 0.1 units of energy.
We now have only 1020 – 100 = 920 particles, but their average KE is 0.872. Notice that it has NOT decreased by 0.1, but by a mere 0.005 (which can be attributed to the crude model and round off errors).
(all numbers were generated by a very simple, quick, crude spreadsheet)
Hi Tim.
I’m not sure what do you mean with:
“The DISTRIBUTION of KE will be the same at different altitudes. This is subtle but critical.”
I agree in case of a GHGs atmosphere where elastic bouncing and consequent radiation could imbalance the KE to PE and viceversa conversions.
When you talk about different thermal energies, if you are talking about the probabilistic distribution of the energy at the surface for the very same temperature, what it changes at any layer is the concentration of molecules, so the density and the pressure of the gases. But at a specific layer the average KE will be always the average KE at the surface minus the PE possessed by those molecules just because they have reached that layer.
Into a non GHGs atmosphere, KE is never lost, but converted to PE during the ascensional process.
If you are arguing that the KE is constant along the altitude because of the average KE of the molecules is the same, then you miss the point that all the molecules are converting their KE to PE and finally also the more energetic molecules must fall to zero KE at the TOA, because they have converted all their KE to PE. When those last molecules reached the TOA and stopped their ascensional run, they can’t still have the initial average KE, as your model suggest, because they stopped their ascensional run because of the full KE to PE conversion, and now they are ready for start a discensional run keeping back little by little their KE from their previously stored PE because of the gravitational field.
I don’t know how do you thought your spreadsheet model, but I believe that it has some issues about the gravitational PE conversion.
Just run it for one molecule and try to see at which altitude that only molecule stops its ascensional run, if its KE was constant along the altitude it never stops at all and escapes forever into the deep space.
Have a nice Sunday.
Massimo
Just to remind everyone, the fact that an atmosphere in thermodynamic equilibrium is isothermal is a rigorous conclusion derived both from statistical mechanics and also demonstrated by the Second Law (i.e., that you can create a perpetual motion machine were there a temperature gradient). Unless somebody can come up with compelling counterarguments to these rigorous conclusions, there is really nothing left to argue about.
What Tim is trying to explain is what is wrong with a simple intuitive argument based on PE and KE that seems to lead to the opposite conclusion. But, the fact is that we know this argument is wrong (for the reasons that Tim has explained) based on the fact that it contradicts rigorous arguments for which there has been no evidence provided that they are incorrect.
Hi Joel,
I still haven’t seen any perpetual motion into the G-driven lapse rate atmosphere. And even placing a TOA-to-surface long thermocouple, you just create an alternative energy path from the non-isothermal atmosphere exactly as the GHGs are doing now.
Are convective loops perpetual motions in your point of view?
Reading Maxwell’s Theory of Heat, he did a theoretical and very superficial explanation of the supposed perpetual motion.
Thank God, climatologist aren’t gunners. Because if they was, the war was surely lost.
A cannonball returns almost all the initial energy to the ground (possibly destroying the targets). It does that not because of the friction to the air molecules, but because of gravity.
In the cannonball trajectory, the GHGs affect the ground radiating the surface with the LWIR produced by the cannonball friction with their molecules, but the reason it fall down and returns the bunch of energy needed to launch it so high, it’s almost all into the gravitational force.
In my opinion any gas molecule in the atmosphere is launched up by the infinite gunners represented by the thermally excited atoms of the surface, and when that molecule terminated its parabola it returns exactly the same KE it received when that nano-gunner launched it (I’m talking about a GHGs free atmosphere of course). So there is a place (the vertex of the parabola, that is the TOA) where that molecule stops its run to restart to the opposite direction.
There, the KE is zero so the temperature of that molecule for an infinitesimal time is zero.
Have a nice day.
Massimo
Massimo says: “Are convective loops perpetual motions in your point of view?”
Yes. And, indeed there are not convective loops in equilibrium. (Note that the Earth is not in equilibrium either with or without greenhouse gases because it is constantly receiving energy from the sun.)
It is important to distinguish what is true in equilibrium from what is true in systems that are being driven and are not in equilibrium.
Hi Joel,
Ok I get your point:
you have a really singular concept of “perpetual motion”.
In my point of view it was a closed system where work was perpetually done without incoming energy from the exterior.
Anyways my point is: if it can exist a convective loop in our current atmosphere because GHGs thermally short-circuits the vertical lapse rate and radiate at different altitude into the space, then it exists into the missing GHGs with the G induced lapse rate when you place a thermal conductive column too. Because that column (maybe the long thermocouple wires) does exactly what the GHGs do today. It radiates/conduces from the TOA altitude to the surface and radiate to the outer space too. The other constraints other than the GHGs are the same, so I don’t really understand why you wonder of the “perpetual motion” in that setup, if you accept “it” into the current one.
Please note that for me the convective loops are NOT perpetual motions, they are just machines driven by the energy flow into the atmosphere.
Have a nice day.
Massimo
Vacuum is one but a hard expensive way to get rid of complex convections around plates.
Another way would be perhaps this:
You’d put plates inside bottom of styrofoam boxes but You turn them upside down so that plate is up and open door of boxes shows down to ground. You put both boxes side by side and over two mirrors. Under the boxes are mirrors (at 45 degree angle) so that one plates IR is reflected from bottom to mirror to another mirror and up to another plate.
AA <– to boxes
\/ <– mirrors, highly IR reflective
If both are warmer than ambient air then warm plates form stable inversion layer up in boxes and convections are practically missing. Only radiation and conduction is left.
If another plate is colder than ambient then You don't need mirrors. You just pust colder plate in box under the hotter plate (and box).
A
:
U
Cold plate forms inversion layers on bottom of box and convections should be minimal, too ..
This would also better model upper atmosphere (where there is not so convective than here down in troposphere) ?
Dr. Roy Spencer.
We will try to demonstrate the energy accounting of the planet without hurting the principles of physics and without invented values.
We start from the observed data:
TOA emission = 240 W/m2.
Issue surface = 390 w/m2
Return of IR from the atmosphere = 360 W/m2.
To demonstrate the energy accounting need to set the minimum parameters of the atmosphere. Let us divide the air into two layers at approximately 5,000 meters, thus: Layer bottom from surface up to 5000 meters. Top layer, the 5000 meters to 15,000 meters. Each layer must absorb 100% of IR emitting 50% up and 50% down, assuming the hypothesis that the atmosphere have differential absorption.
In this condition the transmittance of the lower layer should be 0.99990 or 0.0001 of average attenuation per meter (0.01%). The top layer, due to its density will present a transmission factor of 0.99970 or an attenuation of 0.00003 per meters (0.003%). It does not matter here if such attenuation is due to gases a, b or c.
Note: Tyndall found an attenuation of 4% in the air from his laboratory.
One final condition: The planet’s surface evaporates water to 8mm per square meter per day as an annual average, causing a convective transport of 210 w/m2 releasing this energy will be 5000 meters at the interface between the two layers of the atmosphere.
Corretion:
The top layer, due to its density will present a transmission factor of 0.99997
Part 2
The initial conditions we set the values.
The upper layer of the atmosphere radiates into space 240 W/m2 and 240 W/m2 to the lower atmosphere and receives from the lower layer 480 w/m1.
The bottom layer receives 240 w/m2 from the upper layer and 105 w/m2 from the interface via convective motion (latent heat) toward low, and 390 w/m2 from the surface toward the bottom up. As the absorption in gases is differential, the lower layer will absorb 390 – (240 +105) = 45 w/m2 which radiate 50% up and 50% down, unbalancing the system, the equilibrium will be achieved when its absorption download 30 w/m2 for allowing the emission from the atmosphere to the surface 240 +105 +15 = 360 W/m2.
Checking, the top layer will be getting 360 w/m2 direct from surface + 105 w/m2 from interface via convective motion + 15 w/m2 from bottom layer totaling 480 w/m2.
The planet’s surface receives from the sun 240 w/m2 + 360 w/m2 from the atmosphere totaling 600 w/m2, radiates 390 w/m2 to the atmosphere and delivers 210 w/m2 to convective motion, totaling 600 w/m2, and the system the whole is in equilibrium.
Not sure where you got 8 mm per day for evaporation, but this site says that annual precipitation (which must very nearly equal annual evaporation) is 1050 mm per year, which works out to ~2.88 mm per day. This reduces your estimate of convective transport from ~210 W/m^2 down to about 76 W/m^2, which is in close agreement with the ~80 W/m^2 that Trenberth and Keehl (http://chriscolose.wordpress.com/2010/03/02/global-warming-mapsgraphs-2/ ) attribute to evapotranspiration. (They attribute another ~17 W/m^2 to “thermals”, i.e., convection not associated with evaporation/condensation.)
Also, the 240 W/m^2 that is absorbed is not all absorbed at the surface…only about 2/3 of it is.
Your simple two-layer model of the atmosphere and the notion that such layers emit the same up and down is also simplistic. An infinitesimally-thin layer has to emit the same amount up and down, but a layer of considerable thickness (such that there is a significant temperature difference between the top and bottom) does not.
Sorry, forgot the link for the average annual precipitation on the Earth: http://hypertextbook.com/facts/2008/VernonWu.shtml
Joel Shore
Thanks for the link.
This difference between the evaporation of 2.88 mm provided the link and my estimate 8mm/dia me worried because in measurements made by me 12mm/dia in Manaus (03 degrees south), 8mm/dia in Vilhena (12 degrees south) and 4mm/dia in Porto Alegre (30 degrees south) forced me to make new measurements and calculations of the weather here in Manaus and amazingly, came across a factor has not seen before. Our preliminary conditions based on a fixed absorption proved erroneous.
The absorption of the atmosphere is variable with the relationship between water vapor and water droplets in the atmosphere. In other words depends on the cloud cover. This problem should generate a new theme for Dr. Roy
Water droplets >> water vapor.
I’m not really sure what you are getting at but if you are saying that water vapor has different radiative characteristics from water droplets, that is well-known.
Hi Joel Shore
Could you provide a link? Dont You.
D’Avila: Here’s one: http://en.wikipedia.org/wiki/Electromagnetic_absorption_by_water
Nobody would ever assume that a liquid and a gas of the same material have the same absorption spectra. The fact that the molecules are in very close proximity in one and not in the other makes a huge difference.
In fact, even the absorption of light by water droplets will be different than that of bulk water, although the differences will in general be less dramatic than that between liquid water and water vapor.
“Also, the 240 W/m^2 that is absorbed is not all absorbed at the surface…only about 2/3 of it is.”
Yes, but it is the only significant energy source so it can be considered to be the same as if it all went to the surface, or if 240 W/m^2 of the 390 W/m^2 gained at the surface comes directly or indirectly from this flux (at least in the steady-state).
No…For the sort of detail that D’Avila is considering (surface energy balance), one does have to consider the detail of whether the absorption occurs at the surface or not. [For doing TOA radiative balance, it doesn’t matter, since you are just interested in the flux in and out at the top of the atmosphere.]
“Your simple two-layer model of the atmosphere and the notion that such layers emit the same up and down is also simplistic. An infinitesimally-thin layer has to emit the same amount up and down, but a layer of considerable thickness (such that there is a significant temperature difference between the top and bottom) does not.”
Yes, but by and large the atmosphere radiates isotropically on a photonic level. The probability of emission is nearly always 50/50 up or down. The exception may be the tops and bottoms of dense low clouds that behave more as a separate black body surface.
We are not talking about at the individual photon level…The problem can become one of photons undergoing multiple emissions and absorptions. At any wavelength where the layer thicknesses that D’Avila defines are optically thick, there will be different radiative intensities up and down.
Each layer must absorb 100% of IR emitting 50% up and 50% down, assuming the hypothesis that the atmosphere have differential absorption.
Repit……..
assuming the hypothesis that the atmosphere have differential absorption
D’Avila,
I think you mean that whatever percentage of incident IR is absorbed by a layer, it must then emit that quantity 50% up and 50% down (on a photonic level). However, a layer with a temperature differential between the top and bottom will not emit the same amount of IR out the bottom of the layer as it does out the top.
What climate science has apparently failed to account for when quantifying so-called GHG ‘forcing’is that the atmosphere radiates its absorbed energy both up and down, and that every joule that goes into the atmosphere – whether initially radiant or non-radiant, has the potential to leave the atmosphere over twice the area it arrives.
RW
We’re talking abaut gaseous body and thinking in solid boy.
A cubic meter of nitrogen (air) contains 44 mols of molecules totaling 2.64 e25 molecules. Extracting the cube root we each 2.98 e9 molecules per edge. A N atom has a radius of 56 e-12 meters, giving an equatorial area of 9.85 e-21 square meters and 1,97 e20 m2 per molecule(N2). Each m2 will have a coverage of 17.4 e-3 cm2 but in a cubic meter will has 2,98 e8 layers. Multiplying 1.74 e-3 x 2.98 e8 = 518520 m2 equivalent. Can we compare??
To correct…
RW
We’re talking abaut gaseous body and thinking in solid boy.
A cubic meter of nitrogen (air) contains 44 mols of molecules totaling 2.64 e25 molecules. Extracting the cube root we each 2.98 e8 molecules per edge. A N atom has a radius of 56 e-12 meters, giving an equatorial area of 9.85 e-21 square meters and 1,97 e-20 m2 per molecule(N2). Each m2 will have a coverage of 17.4 e-3 m2 but in a cubic meter will 2,98 e8 layers. Multiplying 1.74 e-3 x 2.98 e8 = 518520 m2 equivalent. Can we compare??
D’Avila,
I’m afraid I don’t understand your point.
Oi!! Joel Shore
In the atmosphere, infrared radiation should be analyzed as Lambertian`s sources or extended sources. With sources emitting surface much greater than the distance that we carried out the measurements. In the case of the atmosphere, each emitting surface is a isotherm surface. In this case, although the particle emit in all directions have the final result only radiation up and down
D’Avila says: “Each layer must absorb 100% of IR emitting 50% up and 50% down, assuming the hypothesis that the atmosphere have differential absorption.”
That is true of an infinitesimally-thin layer. However, you divided your atmosphere into two very thick layers. In that case, the emission up and down doesn’t have to be 50-50 because the temperature at the top and bottom of the layer is different.
RW says: “What climate science has apparently failed to account for when quantifying so-called GHG ‘forcing’is that the atmosphere radiates its absorbed energy both up and down, and that every joule that goes into the atmosphere – whether initially radiant or non-radiant, has the potential to leave the atmosphere over twice the area it arrives.”
This is just a silly claim. All models, from the simple shell model to full-fledged radiative-convective models quantify this sort of thing correctly.
Joel,
Climate science quantifies a watt of incremental GHG absorption to be equal to incremental GHG ‘forcing’ or equal to a watt of post albedo solar power. This is arbitrary and not really valid for the reasons I mentioned. The quantification of the upwelling flux absorbed by the atmosphere is about 300 W/m^2, for which the 3.7 W/m^2 from 2xCO2 is in addition to, yet the surface only gains about 390 W/m^2 with 239 W/m^2 being supplied by the Sun. The difference is 151 W/m^2 – not 300 W/m^2.
A key consideration that few seem to note is the power gained at the surface is the same as the power radiated at the surface in the steady-state (assuming surface emissivity of 1).
Not sure what you are trying to say here but I am finding your statement hard to interpret in a way that is correct.
What ultimately makes the surface temperature about 288K if not the power gained at the surface?
Which must be about 390 W/m^2 to sustain 288K.
Okay…I guess the problem that I had with your statement is that you said, “the power gained at the surface is the same as the power radiated at the surface in the steady-state”. I interpreted “power gained” as the total inflow of energy to the surface and that is not equal to just the power radiated but rather the total amount of power leaving the surface, which includes ~97 W/m^2 due to convection (including evapotransporation), as per the Kiehl and Trenberth diagram: http://chriscolose.wordpress.com/2008/12/10/an-update-to-kiehl-and-trenberth-1997/
OK. All I’m saying is the *actual* power supply to the surface (i.e. that which determines the surface temperature) is the net and not the gross. For 288K it’s about 390 W/m^2.
We set the initial conditions to values.
“Bat…..rectified
The surface evaporates 2.88 mm/hora/m2 carrying 75.2 w/m2 and the atmosphere in the lower layer (0 to 5000m) water droplet evaporates the ratio of 5.12 mm/hora/m2 absorbing solar flux 134.8 w/m2.”
The upper layer of the atmosphere radiates into space 240 W/m2 to 240 W/m2 to the lower atmosphere and 480 w/m2 receives from the lower layer.
The bottom layer receives 240 w/m2 upper layer over 37.6 w/m2 interface via convective motion (latent heat) toward low top pair and 390 w/m2 from the surface toward the bottom up over 67.4 w/m2 processing droplet of water vapor .. As the gas is differential absorption in the lower layer will absorb 390 – (240 +37.6 +67.4) = 45 w/m2 to radiate 50% up and 50% down, unbalancing the system to reach equilibrium that will be achieved when its absorption download to 30 w/m2 leaving the emission from the atmosphere to the surface 240 +105 +15 = 360 w/m2.
Checking the upper layer is receiving surface 360 w/m2 direct + 37.6 w/m2 interface via convective motion + 15 w/m2 lower layer + 67.4 transformation of water into steam droplet totaling 480 w/m2 .
The planet’s surface receives from the sun 105.2 w/m2 + 360 w/m2 atmosphere totaling 465.2 w/m2, radiating 390 w/m2 to the atmosphere and delivers 75.2 w/m2 for convective motion totaling 600 W/m2, and the whole system will be in balance.
Only remains the question: But what is the cause of the warming of the oceans?
The ocean is warming due to displacement of the evaporation of the continent to the ocean due to soil sealing.
Corretion
The surface evaporates 2.88 mm/dia/m2 carrying 75.2 w/m2 and the atmosphere in the lower layer (0 to 5000m) water droplet evaporates the ratio of 5.12 mm/dia/m2 absorbing solar flux 134.8 w/m2.”
Tim Folkerts said:
“Of course, they (molecules) lost some of that initial KE on the way up. The net result is that the few particles that DO reach this level STILL have the same average KE as greater number of particles near the surface.”
They didn’t ‘lose’ KE. It became gravitational PE. They have the same total energy (KE + PE) as they had at the surface.
and:
“Increasing the density doesn’t change this basic result. The self-selected particles with enough energy to get to the higher altitudes will lose exactly enough KE to maintain a constant temperature (at the expense of decreasing pressure and density)”
You need to consider adiabatic uplift. The more energetic particles convert KE to PE with height at the same rate as all the less energetic particles around them so that if no energy is added or lost they remain proportionately warmer than the particles around them and continue to rise.
They only stop rising when they hit a temperature inversion such as the tropopause or top of atmosphere where they cool to the temperature of space. Radiative capability has no effect because the molecules absorb and radiate at the same rate for a zero net effect on total energy(KE + PE) content. The extra KE content was derived only from the initial conduction from an unevenly heated surface.
In reality all atmospheres contain one or more inversion layers, often many, due to compositional variations so a clean route to ToA is never achieved.
Then comes the bit that you and many others seem incapable of grasping.
Having risen in one location air descends in another on a 1:1 ratio so the descending air warms up as it converts gravitational PE back to KE.
The newly released KE on the descent is what keeps the surface warm. Not downward radiation.
Hi Stephen,
I agree with you.
In fact, the isothermal atmosphere shouldn’t have any thermal inversions layers. So, what should it stop the molecule to rise forever, if they don’t convert their KE to PE?
Even if the upper molecules should exchange the residual KE (the other is converted to PE) with the underlying molecules, the final averaged upward/downward exchange of vertical KE should be zero. That because the excitation temperature at ground was the same for all the molecules involved into the KE exchange. Without GHGs all the molecular bumps should be considered anelastic, so since no frictions should be experienced there, then no KE lost at all. For that, into a missing GHGs atmosphere, at any altitude layer should be associated a specific KE, that is a temperature, inversely proportional to the highness of the specific layer.
…Or not?
Have a great day.
Massimo
Hi Massimo.
It really is astonishing that there is such ignorance of the effect on temperature of a pressure decline with height.
And the simple, obvious fact that the pressure and temperature decline with height ensures that there will be convective overturning from an unevenly heated surface even without GHGs and so no isothermal atmosphere is possible.
Hi Stephen,
“And the simple, obvious fact that the pressure and temperature decline with height ensures that there will be convective overturning from an unevenly heated surface even without GHGs and so no isothermal atmosphere is possible.”
If you are talking about the different temps as function of the latitude I fully agree. They should be there even in a missing GHGs atmosphere because of the different distribution on the almost spherical surface.
Note that if the isothermal atmosphere didn’t exist, it doesn’t means that the GHGs effect doesn’t exist at all. The contrary, it could be the reason that the models mispredicted the mid-tropospheric hot spot.
That is, the GHG effect could exist, but it could be less influential than the gravitational lapse rate along the altitude, so the hot spot could be there, but it could be overcompensated by the G lapse rate.
Stephen says: ” They didn’t ‘lose’ KE. It became gravitational PE. They have the same total energy (KE + PE) as they had at the surface.”
But temperature relates ONLY to KE, not PE. So the amount of PE they may or may not have is immaterial for finding the temperature.
“You need to consider adiabatic uplift. “
We are discussing the equilibrium state. The equilibrium state can have no convection.
Now, there could be steady-state situations (NOT equilibrium) where there is continuous convection, in which case a permanent lapse rate is certainly possible. For example, cooling at the top and heating at the bottom, or cooling on the night side of a rotating planet and heating on the day side.
But to repeat myself, thees are NOT the equilibrium situation.
Tim,
it is not convection, it is molecular run upward due to the bouncing of the molecules. It is always needed to keep the gases molecules at a certain altitude against the gravitational force, otherwise they collapse down to the surface.
In absence of GHGs the gases molecule don’t freeze in their position, they need always to run to keep a certain distribution, and into a gravitational field they need an upward run to stay at a certain altitude.
And since, as you said, PE isn’t temperature at all the isothermal atmosphere shouldn’t exist at all too.
It’s an energy equilibrium, exactly as now with the GHGs, only that GHGs shorten the energy between layers and allow energy lost to the outer space too.
The Sun supply energy, not temperature, which is just a proxy measurement of the amount of energy which permeate the matters.
Anyways, that’s just the way I understood it, maybe I’m wrong.
Have a nice Sunday.
Massimo
Stephen says the newly KE on the descent keeps the atmosphere warm ,not downward radiation.
Wrong Stephen. Again if you have the planet earth and in case one it has zero ozone ,zero water vapor and zero co2,and other ghg ‘s and in case two it has ozone,watervapor and co2 among other ghg’s you are NOT going to have the same atmospheric temp. structure/climate/weather, for the earth in case one and case 2.
That despite all other factors of the earth in case 1 and 2 being the same.
Stephen how sucessful radiative processes may or may not be(in producing x warmth) depends on the composition hence structure of the atmosphere and the albedo of the surface /atmosphere of the earth itself.
That is where it is at, and yes the ghg’s warm the lower atmosphere while cooling the upper atmosphere, which in turn will enhance convection and keep the atmosphere in motion.
Stephen you still can’t explain why the surface temp. of the earth is 288k versus 255k given the solar radiation.
Hi Salvatore,
I don’t know what are the other dynamics of the atmosphere which regulate/modify the temperature at ground, what I infer is that the climate models seem to take the isothermal atmosphere as a consolidated fact. If it was, then they could be wrong.
“Stephen says the newly KE on the descent keeps the atmosphere warm ,not downward radiation.”
I guess they could be both, because if molecules of water vapour is forced up by ascensional winds could condensate and when they release their heat by radiation and thermodynamic diffusion to the surrounding gases (GHGs and not) that air mixture could behave as does the Foehn wind.
Please note that in case of the Foehn winds the side of the mountain which gets the “back radiation” of the condensed water isn’t the warmed surface(maybe because of the induced rain of course), so it seems that the radiative path isn’t so efficient in heating the surface.
Sorry, I still haven’t found any proof of a only radiative energy path from the tropopause to the ground.
And I still would like to see the effective global averaged outgoing LWIR radiation, not the normal transmittance of the atmosphere as seen by the satellites at the at the nadir of the TOA.
Have a nice weekend.
Massimo
Massimo.
GHGs affect the circulation but not the average temperature.
The circulation change is a negative system response which prevents further system warming. The amount of energy held in the atmosphere in PE form is capable of varying oppositely to any effect that GHGs might have whether net warming or net cooling. The mechanism is an increase or decrease in the amount of convective uplift.
In theory GHGs warm the lower atmosphere and cool the upper atmosphere but that increases the vertical temperature gradient which results in those circulation changes as a negative system response.
It is now looking more likely that the stratospheric cooling of the late 20th century was solar induced rather than GHG induced and that solar influences on circulation (and probably oceanic influences too) dwarf any effect from human emissions.
However any forcing element that seeks to upset the average global surface to space temperature gradient will result in circulation changes but only more mass, more gravity or more ToA insolation results in a rise in surface temperature and system energy content.
Hi Stephen,
as I already said, I’m just an electronic engineer.
Before this passion for the climate issue, I limited the use of the thermodynamic physic just for the computation of the dissipative requirements of the board I designed. And to be honest that was a very approximate use of that science.
I know that you are an estimated professional meteorologist, so you surely know better than me how to approach to the atmospheric dynamics.
For what’s my knowledge I agree with you, but I would like to have an experimental proof of all we say here (as yourself stated indeed).
Have a nice day.
Massimo
Salvatore,
I said before that the weather/climate would indeed be different for a planetary atmosphere with GHGs and one without.
My point is that GHGs affect circulation and not system energy content.
That is consistent with your comments.
The surface is 288k versus 255k for the solar radiation simply because the exchange of energy between the surface and the mass of the gases in the atmosphere induces an amount of delay in the throughput of solar energy that causes a rise in surface temperature of 33k.
It is the mass that causes the delay rather than the radiative characteristics. The latter merely cause a circulation change as the system reconfigures to negate their potential thermal effect.
Stephen I think GHG gasses are not a source of energy for the earth climate system and do not add energy to the earth climatic system.
Here is where I think our difference is. I say unlike yourself that the GHG trap EXISTING ENERGY in the earth climate system and direct this energy back again to the surface rather then allowing it to escape directly to space thus keeping the surface and lower levels of the atm. warmer then they would be otherwise.
I also disagree that the mass of the atmosphere translates to the 33 degreec temp. difference.
I maintain if the mass of the atm. were not to change but the chemical composition of the atm. were to change that the 33c temp. difference would change, it would not remain the same.
The 33c temp. difference in simple terms is due to the fact that original energy coming into the earth and thus to the earth surface does not flow back out to space directly but gets circulated back again toward the surface.
HOW EFFECTIVE THIS IS DEPENDS ON THE COMPOSITIONAL MAKE UP OF THE ATMOSPHERE IN MY OPINION, WHICH IN TURN IS DEPENDENT IN LARGE DEGREEG UPON THE AMOUNT OF ENERGY IN THE CLIMATE SYSTEM TO BEGIN WITH ,WHICH DEPENDS ON THE INTENSITY OF SOLAR RADIATION VERSUS THE ALBEDO OF THE EARTH/ATMOSPHERIC SYSTEM.
Stephen if the mass of the atmosphere of earth were the same but one was devoid of all greenhouse gases while the other had greenhouse gasses the 33c temp. difference or whatever difference, would not be the same.
That is my opinion.
You are saying regardless of the atmospheric makeup of the earth the reason why the temp. is 33 c higher is due to the mass of the gasses of the atm., regardless of what kind of gasses are in the atm. You are saying mass determines the diff. only. Is that correct?
For example, here’s a comparison for downward IR flux at the surface between the HadCM3 model and 41 Baseline Surface Radiation Network (BSRN) stations:
In this case, the model underestimates the downwelling sky radiation by about 9 W/m2. But for something supposedly “non-existent”, there is remarkable agreement between the average model behavior and
STEPHEN HOW DO YOU ACCOUNT FOR THAT???
Salvatore.
We disagree on the effect of GHGs.
You consider that GHGs contribute most if not all of that 33C.
I say that GHGs contribute little or none of that 33C and that it is mostly or all due to atmospheric mass.
In my opinion mass determines that the thermal enhancement is 33C whereas atmospheric composition determines the distribution of the additional energy within the system.
Radiative characteristics are just one of the compositional variants that can affect energy distribution. Another is the specific heat of the water in the oceans which should also be regarded as part of the atmosphere since they are partially transparent to incoming solar shortwave. Another is the phase changes of water. Another is the specific heat of the various gases and airborne particles in the air. Another is the ability of ozone in the stratosphere to react directly with incoming solar shortwave.
All those compositional variations and many others naturally influence the global air circulation and thus weather and climate.
The radiative characteristics of our CO2 emissions are relegated to insignificance in comparison especially when one adds in solar and oceanic variations.
But at base that mass induced 33C thermal enhancement overrides all other influences apart from gravity and ToA insolation.
We cannot resolve that difference here but must await further developments in the science and the observational data.
Stephen,
“We cannot resolve that difference here but must await further developments in the science and the observational data.”
Well said.
I believe that the observational data are the only way we should use to understand the dynamics of the energy balance of our atmosphere.
IMHO we should first learn to do the right measurements of the TOA outgoing LIWR, so we could say if the GHGs really trap or not any energy flux and in case how much, and then we will say who is right or wrong.
Have a nice Sunday
Massimo
The data is there and it is already resolved. All the data in the world cannot cure the problems that you have because they are fundamentally not scientific issues but problems of basic scientific comprehension.
Hi Joel,
“All the data in the world cannot cure the problems that you have because they are fundamentally not scientific issues but problems of basic scientific comprehension.”
Ok, came on and tell me where I’m wrong.
As far I know satellites has very little field of view, so most of the GHGs outgoing LWIR radiation could be unseen by their input slits.
I already wrote this many times on this blog, so I didn’t want to reply myself one more time. Anyways there is a big difference between normal and diffuse transmittance, AFIK satellites measure the normal.
Ask yourself why the most prominent spectrometer producers invented specific spectrometers having an integrating sphere in front of their inputs slits for gases transmittance and reflectance measurements.
Take a spectrometer like the one installed on the satellites, calibrate it versu a parallel rays LWIR source (or even slightly diverging one), then place a perfectly LWIR clear plano-concave lens so that its flat face is facing the slit of the spectrometer and see what it happen. In no ways that means that the lens has reflected back anything, but the spectrometer surely measured a lower averaged flux because of the unseen diverged rays. And even if you move away the slit from the lens optical axis, you still get lower power measurements. GHGs do almost the same thing into the atmosphere (not the same of course, but under the rays spreading point of view they do).
Just to be honest till the end, I never did that at the LWIR band, just at the near IR / visible band, but I guess it should be the same into the LWIR spectrum.
I don’t know if GHGs doesn’t traps any energy at all as Stephen argues, I’m not an atmospheric physicist, I just say that I don’t find any proof of the trapping that you say exist for sure, not till today.
Maybe be you are right and I’m wrong, but until you don’t let me see what’s the diffuse spectrum at the LWIR of the whole Earth dish, especially at the poles, your opinion is not more valuable than mine. It’s just an opinion.
As a direct professional experience, the failures of some experimental checks, fallen into the details not into the main theory.
IMHO a good scientist should never reject a supposed issue just because of his/her academic status, but explaining why the issue isn’t an issue at all.
Have a nice Sunday.
Massimo
All,
Well, let’s see…
Salvatore/Joel/Tim and maybe Dr Spencer(?) think that GHG radiative factors play a significant attributable part in the formation of the ‘GHE’ of 33C.
Stephen/RW/John K/Massimo and I think that GHG radiative factors do not play a significant part.
I hope I haven’t misrepresented anyone, at least in spirit.
What is significant?
Warmists such as Trenberth, Schmidt, scienceofdoom, say CO2 alone equates to 26% of GHE.
Lacis is close behind with 20% for CO2 and a further 5% for the other non-condensing GHGs.
Lukewarmists (plenty on the ‘Blackboard’) say radiative factors play a fairly significant part, and will claim a ‘climate sensitivity’ of around 1.2C, but prevaricate on allocating a ‘percentage of GHE’.
Stephen Wilde says that radiative factors play an insignificant (almost zero) part in the ‘GHE’.
So lets look at the data:
‘Accurate’ records’ began in 1850 (according to the IPCC), meaning the HadCRUt3 dataset (recently replaced by HadCRUt4). Those records (both) indicate a rise of 0.8C since 1850.
Contemporaneously (but not necessarily correlated), non-condensing GHGs have risen significantly (40% CO2, 150% CH4 to name the two main players). I hope no-one disagrees that those percentages are significant.
Can we correlate the 0.8C with the rise in nGHGs?
Yes, according to Joel Shore. No, according to me.
As my supporting evidence I point out that the HadCRUt data shows a rise of 0.7C between 1910 and 1945, well before the increase in CO2 started to accelerate. Logically, therefore, the 0.7C rise between 1975 and 1998 (same rise, slightly shorter period) cannot be asserted to have been caused solely by CO2. All that can be reasonably (objectively) stated is that CO2 ‘may have been responsible for an unknown portion of the rise’. It CANNOT be all of the rise because that would deny the possibility of whatever factors caused the earlier rise, and the ensuing flattening has to be due to ‘other factors’ also. Equally, it CAN be due to virtually the same factors which caused the earlier rise.
As there was a ‘GHE’ (or an ‘Atmosphere Effect’ at least, before 1850, we are left with the likelihood that most, if not all of the 0.8C rise has been due to those ‘other’ factors (such as natural factors). This means that the significant rise in nGHGs has not been correlated with a significant rise in global temperature. It also begs the question “How could Trenberth et al seriously attribute a 26% contribution for CO2 alone, which would equate to over 8.5C out of 33C?” If 280ppm (in 1850) equates to 8.5C, why hasn’t a 40% increase led to a greater rise in temperature than “…an unknown portion of 0.8C”? (If you want to attribute a smaller contribution percentage in 1850, then please give a figure…)
Therefore, it seems perfectly logical to me (as an objective non-scientist) that the data supports Stephen Wilde’s view to a greater extent than it supports the assertion that radiative physics plays a significant role in the 33C ‘GHE’. There is no real-world (non-modelled) evidence to support the ‘radiative physics is King’ view, particularly in any quantified sense.
No evidence = no credibility.
Stephen Wilde’s view has at least some support from observed evidence.
Be objective.
Regards,
Arfur,
for what it worth. I’m by your side.
Have a nice Sunday.
Massimo
Massimo,
Thanks very much.
You too! 🙂
Arfur
Arfur,
Regarding the +33C surface, I agree with Dr. Spencer that it is radiatively induced (i.e. from GHG absorption and downward re-radiation).
RW,
Very sorry to have mis-represented you!
So would your position be that the 33C is exclusively due to radiation? (If you removed all GHGs there would be no ‘Atmosphere Effect’? Just curious.
Regards,
Arfur
Data and observation is all that matters to me.
No ideological position at all.
If the AGW proponents were right I would have no problem supporting remedial action.
But I don’t think they are right.
Hi Arfur,
You stated:
“Salvatore/Joel/Tim and maybe Dr Spencer(?) think that GHG radiative factors play a significant attributable part in the formation of the ‘GHE’ of 33C.
Stephen/RW/John K/Massimo and I think that GHG radiative factors do not play a significant part.”
To clarify, the 33C claim involves speculation as to Earth’s temperature with and without so called green-house gasses. I do not merely question the effect green house gasses have on temperature but any claims as to the what that temperature difference might be including the supposed 33C GHE as well. Scientific knowledge comprises the facts and laws of nature only. Any theoretical and/or speculative claims may provide ideas as to further tests and/or exploration, but do not comprise knowledge. Such speculation merely represents guesswork, nothing very meaningful. Even purported observations must be treated with skepticism and experimental results questioned and repeated for hopefully improved data accuracy, to avoid error and to lead one to further ideas as to how future experiments may be better designed and implement.
BTW, everyone would do well to review the Socratic/scientific method. Skepticism of all “things” rests at the heart of it.
well most of the time people who deniys backradiation begin doing a mistake, for instance they imagine that the rate any warm object loose engy is given by some kind of law…
well for instance a bulb…
the first question you have to answer is what is the temperature of the bulb ?
to answer this..you have to do an energy budget and come to the conculsion that the temperature of the buld depends on what surroundd it!
and when you do that you can also see that the temperature of the bulb doen’t really exist it is not the same everywhere at its surface!
dragon slayers just miss the first step.
Had another go at the steel greenhouse experiment. Documented here:
http://climateandstuff.blogspot.co.uk/2013/06/the-copper-iron-green-house-revisited.html
Using a grey (Black body) plate as steel greenhouse the heated body temperature rises 3.5°C
Using a reflective plate (similar to light bulb experiments of watts) the heated body temp rises 5.5°C.
I said, the current GHG effect that is present today has caused the temp. of the earth to be around 33c higher then it would be otherwise.
I also say due to the present GHG situation that it is now exhausted in be able to produce a further significant temperature rise from here.
Main reasons being that water vapor concentrations are going to be unable to increase from here, while co2 concentrations are near saturation for the IR wavelengths it absorbs.
This is ironic because on the one hand water vapor could absorb more IR if it were to increase in concentrations but it can’t, while CO2 can increase in concentration but can’t absorb much more IR.
Hence the GHG effect is exhausted given the present situation.
Present situation baseD upon the amount of energy coming into the earth climate system from the sun,versus the amount of energy leaving the earth climate system based on the albedo of the earth/atm.
Nearly everyone, (including myself until a year ago) is still sucked into the line of thinking first thrust upon the world by the AGW crowd, namely that it is all to do with radiative forcing. Yes, this includes virtually all PSI members – with one notable exception.
I have been thinking this through for a long time and am now firmly of the opinion that all these energy budgets are incomplete, mainly because they don’t show the missing link. On Venus and Uranus that missing link is a huge amount of energy which must flow downwards in the atmosphere. It’s quite a lot on Earth too. Over the life of these planets there has been a build up of thermal energy from the Sun which can’t escape.
So these planets (Uranus, Venus, Earth) are not still cooling off. It’s cold out there where Uranus is because it only receives about 3W/m^2 in the very top of its atmosphere. It could easily have cooled off, but for the one thing that stops it. And that one thing is the gravitationally induced thermal gradient which forms by diffusion at the molecular level,, because molecules in free flight between collisions interchange kinetic energy and gravitational potential energy. In just two lines of calculations, you can derive the -g/Cp value by equating PE and -KE. Kinetic energy will tend towards being homogeneous during collisions, but only at each altitude. Inter-molecular radiation reduces the gradient by up to about a third, but by less than 5% on Uranus where there is just a little methane causing that.
The Clausius (hot to cold) statement of the Second Law is not comprehensive and for conduction and diffusion it only applies in a horizontal plane. The process described in the Second Law means that thermodynamic equilibrium evolves spontaneously, and, in the process of maintaining such equilibrium there must evolve a temperature gradient. Most importantly, extra energy absorbed at higher altitudes can actually flow up this gradient because that will help restore the equilibrium.
The primary determinants of atmospheric and surface temperatures are then based on the autonomous thermal gradient and the overall level of the plot of temperature against altitude. This level is set by the need for radiative balance and, in general, radiative balance cannot be disturbed by internal processes, such as back radiation.
A planet’s surface temperature just depends on where the plot of temperature against altitude intersects the surface. On Uranus the temperature at the base of the theoretical troposphere is about 320K. This is all in line with calculations, and, if there were a surface there, then it too would be 320K – hotter than Earth’s surface, even though no direct solar radiation even reaches down there through 350Km of atmosphere that’s mostly hydrogen and helium. There is thought to be a solid core with about half the mass of Earth, but that’s roughly 20,000Km further down and it may be about 5000K.
So, as on Venus also, where it’s about 730K at the surface, the temperature of a surface is all to do with the height of the atmosphere through which the thermal gradient reaches hotter and hotter temperatures the further it gets to the surface. It has nothing to do with radiative forcing. It has nothing to do with any greenhouse effect. It has nothing to do with carbon dioxide.
A colder body can stop a warmer body from cooling but it cannot make the warmer body warmer.The maximum effect possible is if the cooler body reflects back all the radiation that the warmer body emits and then the warm body will remain at the same temperature with a small increase for the initial temperature of the colder body,if the colder body does not send all the radiation back to the warmer body then the warmer body will cool but will be warmer than if the cooler body was not there but if the cooler body is not there than the warmer body will cool at its normal rate.
You are correct if these are the only two bodies interacting. However, if you have a 3rd body, like the sun, then indeed the combined action of the sun and the colder body (atmosphere) will determine the steady-state temperature of the Earth. And, a change in temperature of the colder atmosphere will cause a change in the steady-state temperature of the Earth.
Yes, more or less, Don. The Second Law of Thermodynamics though is only strictly implying that heat transfers from hot to cold in a horizontal plane when considering conduction and diffusion. The usual version of the law (see Wiki) says nothing about “hot to cold” – it talks about spontaneously evolving thermodynamic equilibrium. However, it is indeed true that radiation has an equalising effect even in a vertical plane, and that means it acts very differently to non radiative processes.
When diffusion in a vertical plane in a gravitational field responds to the “spontaneous evolving” in the Second Law, a temperature gradient develops tending towards -g/Cp where Cp is weighted mean specific heat. However, intermolecular radiation has an equalising effect and on Earth reduces the magnitude of the gradient by about a third, on Venus by about 15% to 25% (as carbon dioxide is not as effective as water vapour) and on Uranus by only about 5% as there is only a little methane there doing the radiating.
Now, the important point is that direct Solar radiation cannot raise the surface temperature to the observed mean temperatures, so we have to ask from what temperature is the back radiation slowing cooling? And, as it cannot slow non-radiative cooling, then will non-radiative cooling accelerate and compensate?
You see Roy, and others – it’s complicated, but, in the big picture, has nothing to do with back radiation controlling mean surface temperatures – because the real process is as in my comments above.
So Roy’s model with its spreadsheet is seriously flawed because it only assumes the restrictions of the First Law of Thermodynamics.
But the real world must also be “restricted” by the Second Law of Thermodynamics. The big misinterpretation about the Second Law by Roy and other climatologists is that they ignore the fact that all statements thereof relate to a system.
Now a system has a very specific definition in physics (see Wiki) and it is either a single process or a combination of processes. But any combination of processes in the system must be interdependent components of the system referred to in the Second Law.
It’s pretty obvious I suggest, that radiation warming something on the surface is not then dictating that any thermal energy deposited there must come back out immediately by radiation. There is no interdependence between these two components, and so they are not a single system to which the Second Law applies. It applies to each system, because there are in fact two independent systems here.
Doug
I feel that energy budgets determining temperature has more to do with the laws of economics than the laws of physics.Many examples have been given where energy equilibrium does not happen that i don’t regard equilibrium as a law of nature.
Your feeling is incorrect, although the term “equilibrium” should be avoided in favor of “steady-state” if the system is being driven (as is true for the Earth’s climate because of the sun).
Hi Don
“A colder body can stop a warmer body from cooling but it cannot make the warmer body warmer.The maximum effect possible is if the cooler body reflects back all the radiation that the warmer body emits and then the warm body will remain at the same temperature with a small increase for the initial temperature of the colder body,if the colder body does not send all the radiation back to the warmer body then the warmer body will cool but will be warmer than if the cooler body was not there but if the cooler body is not there than the warmer body will cool at its normal rate.”
First of all, I’m not an AGW believer.
But I personally did an experiment in my home workshop which seems to contradict your statement above. At least when the system is not limited to the formalism of the two bodies alone. That is, if there is an external energy source (such as the Sun which supplies SWIR & visible photons to the Earth atmosphere), the warmer body became warmer if you place a LWIR reflector in front of one or more of its radiant surfaces.
To prove it, I vertically placed one very thin resistor (its thickness was about 1mm) which was almost squared shaped sized about 25mm on each side. The resistor was mounted suspended on few cm above the desk to allow the airflow to do its cooling effect. Well, after I supplied it a constant regulated power supply so the resistor started to dissipate about 1.13W, it reached a temperature around 55-60°C (I don’t remember this value for sure because now I’m not at home and can’t tell you the exact value).
Then, I placed the LWIR opaque flat face of a heatsink at 12mm from one of the radiant faces of the resistor and I seen not measurable changes in the resistor temperature, but when I stuck an adhesive aluminium tape to that flat face of the heatsink to make it a mirror, despite the thermodynamic setup almost didn’t changed (the tape was 25um thick so the distance from the resistor was almost the same), then the resistor temperature rose of about 1°C.
I repeated the two setups three times and always I got the same result.
Note that I don’t claim to having demonstrate that LWIR photons which exited the resistor and heated the heatsink had been returned to the resistor and warmed more it, but in my opinion I demonstrated that if you place a mirror in front of the resistor, its LWIR photons seems exit and reenter the resistor structure warming more it.
Have a nice day.
Massimo
By the way,
Doug, nice to read you again.
I would like to know your opinion about the experiment I did. It seems to me that at least if the photons don’t lose energy interacting with the reflective surface, they can reenter their source body; and so it seems that a first surface mirror can really warm a body warmer than itself, just reflecting its own photons.
Have a nice day.
Massimo
As far as I’m concerned, all discussion of radiation is just a red herring, as I say it has nothing to do with climate. You probably won’t know why I say that until you understand “Planetary Core and Surface Temperatures.” But I’ll respond to your question, so long as you understand that I don’t believe it has any relevance to climate.
I spent a lot of time researching and writing a paper about “Radiated Energy and the Second Law of Thermodynamics” published on several sites in March, 2012, so you should be able to find it in a search.
I get the impression that you don’t understand what the “system” is in statements of the Second Law of Thermodynamics. A “system” in physics must have interdependent components. The incident and reflected radiation does indeed qualify as a system and the Second Law says that it will spontaneous evolve towards the state of maximum available entropy. So it is impossible for the reflected radiation to cause entropy of the system to decrease and thus the source of radiation to become warmer. By the way, reflection is interdependent, but spontaneously emitted radiation can never be just an interdependent component of a larger system, because heating an object in Earth’s environment does not force it to shed its heat by radiation instantaneously – it could lose some much later by independent non-radiative processes.
Hi Doug,
yes, even if I admit that I don’t have read your paper, I know your point of view.
In fact I explained that I’m not arguing about the two bodies closed system which Kirchhoff law refers to. The system setup was made of the resistor (the warm body), the heatsink (the cold body), the power supply which gave the energy into the resistor and the room which was the drain of the dissipated resistor energy.
What is significant for me is that indeed the photons reentered the resistor, because I measured its temperature by means of a thermocouple placed on the opposite side of the resistor, the side which always faced the surrounding room wall.
So it seems to me that effectively, placing a first surface mirror in face of a radiating object it works such has it reduces its dissipating surface. Which leads to an increased temperature of the object in case it is subject at the very same incoming energy flux established before the mirror placement.
Have a nice day.
Massimo
My “point of view” which you think you know is that the Second Law of Thermodynamics describes a process which enables thermal energy absorbed in the atmosphere to get to the vicinity of the surface, or lower in the atmosphere of gaseous planets as it spontaneously re-establishes thermodynamic equilibrium as the Second Law says will indeed evolve spontaneously. Thus scientists around the world can now understand how planetary atmospheres, surfaces, crusts, mantle and cores retain their temperatures.
Is that what you “knew” was my “point of view” without reading my 20 page paper?
Massimo, if you really want to understand what happened in your experiment you need always to remember that there is a maximum temperature to which a source (Sun) of radiation (or electrical energy in this case) will heat an object (or Earth’s surface.) You may have at first observed 60°C but it may have been capable of heating it to 62°C but then there was a cooling of 2 degrees by conduction and radiation to the surrounding regions. The small resistor at room temperature would make no significant difference to that 2 degrees of cooling. However the mirror could very easily slow that rate of cooling so that the temperature only came down 1 degree from 62°C, but it looked to you as if it was warming from 60°C to 61°C.
Direct Solar radiation from the Sun cannot …
(1) Heat the base of the Uranus troposphere to 320K
(2) Heat the surface of Venus to a mean of 730K
(3) Heat the surface of Earth to a mean of 288K
Hence there is simply no issue regarding radiation from the atmosphere slowing cooling that was caused by direct insolation. You have to look for another process that can and does warm all (1) to (3) and you will learn about it in my paper about planetary temperatures.
Ok, I get your point.
You are arguing that the mirror just changed the energy dissipation path, but it did it because the source was allowed to rise the temperature of the resistor to that value, while you arguing that the sun couldn’t do it.
I’ll think about a little more.
Thank you.
Massimo
MP: When you wrote “It seems to me that at least if the photons don’t lose energy” can’t you understand that this is only applying the First Law of Thermodynamics? You don’t have to think about photons – you have to think about the Laws of Thermodynamics. You can’t just invent a series of independent components, which thus do not form a “system” and so do not excuse a violation of the Second Law because it is inapplicable. The Second Law has to be applied and not violated by any system, where a system has a very precise definition in physics, as I have discussed in an earlier comment.
So what you and Roy and all the pseudo physics of climatology is TOTALLY DISREGARDING is the process in statements of the Second Law of Thermodynamics as it applies to a system of one or more interdependent components. In most cases you have only one component – namely one-way radiation. The electromagnetic energy in such radiation can only be converted to thermal energy in a cooler target. That’s physics.
Yes, I already replied that I get your point.
I just need time to reply to you because I’ve problems with the language and I need a little to make the things right in my statements. 🙂
Have a nice day.
Massimo
“The electromagnetic energy in such radiation can only be converted to thermal energy in a cooler target. That’s physics.”
No, that is poppycock!
A 10 um IR photon gets absorbed by an object independent of the source of that photon. A 200 K object might have created that photon; a 300 K object might have created that photon; a 1000 K object might have created that photon. The photons don’t carry a label saying “I came from an object with temperature ‘x'”. So there is no way for the receiving object to know to accept or reject a photon based on the temperature of the source. So the receiveing object will convert ANY 10 um photons to thermal energy equally, independent of the source of that 10 um photon.
**********************************************
” …TOTALLY DISREGARDING is the process in statements of the Second Law of Thermodynamics… “
You were so close!
The “process” in this case is “exchange of photons”. The exchange of photons must (if we believe the 2nd Law) always result in the net transfer of energy from warmer objects to cooler objects. And of course, that is what happens:
Q = εσ(Th^4 – Tc^4) >= 0
(give or take a few factors related to geometry).
“Let there be a boundary with such-and-such dimensions, with such-and-such conditions regarding energy and mass flows, such that the system of interest lies within this boundary”, and so on…
physics of science you are full of BS!
Massimo Porzio
There are two bodies a hotter body and a cooler body you say the cooler body is a LWIR reflector, so the cooler body reflects all the radiation sent in its direction by the warmer body but the cooler body still radiates towards the hotter body at its own temperature which will cause the warmer body to heat up without warming the cooler body.Have you tried the experiment without an external source?
No Don, of course.
I told you that I was talking about a system not limited to the two bodies, as the atmosphere seemed to be to me.
Anyways, in my case I can’t say that the cooler body has warmed the warmer by it’s own radiation, but just by reflecting the radiation of the warmer body.
In few words I reduced the radiation capability of the warmer body respect the environment reducing the size of its faces to the surrounding room.
Have a nice day
Massimo
Physics_of_Science,
Can I assume that your surgery went well, Doug? 7th July, wasn’t it? I hope so. I for one am glad to see you back. I like the dimension you bring to the debate.
Can you suggest anything I can read which will conclusively explain that radiation from a cooler source cannot be absorbed for net energy gain by a warmer object? My problem with the ‘backradiation’ concept is this:
Thermal radiation is emitted from a warm source and absorbed for net energy gain by a cooler object. The backradiation concept is that, as the object warms, it will re-emit radiation which will allegedly then be absorbed by the source. However, the re-emitted radiation is obviously (by definition) emitted at a lower (cooler) energy level than the original source and I am not sure that such absorption (if it takes place at all) can possibly add to the source’s energy level. I suspect that it is similar to adding a cup of (backradiation) water at 6C to a cup of (original source) water at 8C. You don’t get a cup of water at 14C!
So my question is where does it say in any science textbook that absorption of a cooler energy adds to the energy level of the source?
If that fact can be established then it could be reasonably argued that the currently popular meme of “backradiation does not warm the source; it merely slows the cooling of the source…” must be due to non-radiative factors, possibly that the object acts as non-radiative insulation.
I’d appreciate any clarification.
Thanks
Arfur It would be best if you started by reading the paper I had published on several websites in March 2012 which is easy to find in the PSI publications menu or by searching “Radiated Energy and the Second Law of Thermodynamics.”
What we find in physics textbooks is of course the Second Law of Thermodynamics which reads …
An isolated system, if not already in its state of thermodynamic equilibrium, spontaneously evolves towards it. Thermodynamic equilibrium has the greatest entropy amongst the states accessible to the system.
Now a “system” in physics comprises interdependent components or just one component. So when energy is transferred from the atmosphere to the surface by, say, conduction at the boundary, thence upward convection it will warm some water vapour molecules which may well radiate some electromagnetic energy back towards the surface. But, if you read my paper, you will see a detailed explanation of the “resonant scattering” (sometimes called “pseudo scattering”) process which immediately re-emits the radiation from the warmer surface so that none of its EM energy is converted to thermal energy, and so there is no heat transfer. What the physics books tell you is that, if there were a transfer of thermal energy in this “component” then the Second Law would have been violated because there is no interdependence between the above two components I have described.
Another way of looking at it is to consider the First Law. When the surface radiates a certain amount of thermal energy to a cooler region of the atmosphere the surface cools. It would need to get back exactly the same amount of energy to warm back up to the original temperature. How is it going to get back more energy?
The Sun cannot warm the surface of Earth with direct radiation to a mean temperature anywhere near 288K. Hence the whole discussion about the atmosphere slowing the cooling of the surface is not relevant to the question, what will the surface temperature reach?
PoC
Thanks for your time. I have read your paper but had obviously not quite sorted that bit out in my (admittedly small) brain.
Glad you’re back.
“My question is this: Will the two hot plates cool at different rates?”
Yes. The hotplate facing the cold plate will cool quicker.
I think your experiment is a little complex with many ‘fiddly’ bits to it. A simpler method, and therefore, less subject to errors is to use 1 hotplate and 1 cold or ambient plate. That way everything is in the exact same position for each ‘run’.
Before the actual test I would run a ‘blank’ on the cooling rate of the hotplate alone. Similarly run a ‘blank’ on the heating rate of the cold plate. This would be done within the apparatus,of course.
As to temperature reading, I would prefer data logging the readings of the hotplate and ‘other’ plate. The ambient temperature at the time of experiment should be noted. If you prefer to keep an eye on things with thermal readings then you could cut windows at both ends of the apparatus to obtain 90 degree readings.
I realise this is more time consuming but…..
Roy may well demonstrate the fact well known by us physicists that radiation from a cooler body can indeed slow radiative cooling of a warmer body. (He will see only a slight effect, however, because there will be plenty of conduction between the plates and the colliding air molecules, and radiation cannot slow non-radiative cooling.) But none of this proves anything about any effect on planetary surface temperatures.
All radiative forcing (greenhouse) models are wrong in regard to the assumptions made relating to planetary surface temperatures. In fact they simply cannot be made to work on some planets like Uranus, and wherever they may “seem” to work, they are in fact partly fudged, because they are not dealing with the real mechanisms that determine planetary atmospheric and surface temperatures.
There are two limitations upon the temperature of a target to which spontaneous radiation can raise that temperature ..
(a) The temperature of the source of the spontaneous radiation.
(b) The radiative flux which the target receives from the source.
The solar radiation received by the Venus surface is only about 10W/m^2 because only about 2.5% of the original TOA insolation gets through the atmosphere. The Venus surface is thus not heated significantly by direct radiated energy from the Sun, and nor is it by radiation from the atmosphere. With only about 2,600W/m^2 of incident radiation at TOA even before reflection, how could the required 16,100W/m^2 of radiative flux at the base of the atmosphere come only from that far smaller incident flux? Energy would be created in the atmosphere.
Instead, what must happen on Venus, Uranus and other planets, is that some of the thermal energy absorbed in the atmosphere from incident solar radiation is spread out by diffusion and convection over a sloping temperature plane which evolves spontaneously in accord with the process described in the Second Law of Thermodynamics. This allows heat to “creep” up that thermal plane, because all it is doing Is restoring thermodynamic equilibrium which had been disturbed. The gravitationally-induced thermal gradient in effect traps energy that has been absorbed from the Sun over the life of the planet, and it maintains the temperature of the base of the atmosphere, which temperature then prevents the surface cooling too much at night, and, in the case of Earth, allows the Sun to warm it by day when the radiative flux is of course more than the mean 24 hour value.
Arfur Bryant says:
“Thermal radiation is emitted from a warm source and absorbed for net energy gain by a cooler object. The backradiation concept is that, as the object warms, it will re-emit radiation which will allegedly then be absorbed by the source.”
Whatever happens to it I don’t think it warms the original source. But it could through other means possibly.
As I see it the warm object radiates the cooler object absorbs and warms. The cooler object will only warm to as much as the source at the point it is was warm as the source it will be emitting everything outward that it gets from inward and the two objects effectively act as one.
Now greenhouse gases might warm the surface, especially at night. Daytime is clearly cooler though than in the absence of greenhouse gases. something can be learned by looking closely at the daytime averages and nighttime averages and comparing them to blackbody standards rather than comparing just the average temperature.
One thing you will find is that warming is likely a very good thing. Most deaths come from the cold and the worst cold comes at night. Days will be cooler because of the night time atmosphere cooling will prompt more daytime convection. So even heat deaths will go down because they occur mostly during the day. If it were robust it would mean less needs for energy to stay comfortable. But I am not going to start selling that yet.
Bill,
Thanks for the info.
[“Whatever happens to it I don’t think it warms the original source. But it could through other means possibly.”]
Agree with the first part; I don’t see how it could warm the source. As for the second part, I think that’s getting into the realms of insulation – possibly!
[“One thing you will find is that warming is likely a very good thing.”]
I couldn’t agree more!
There is no “inevitable climate catastrophe” supposedly due to carbon dioxide which does nothing but have a net cooling effect of the order of 0.002 C degree.
You all need to make a paradigm shift in thinking, and find the real reason why temperatures are as they are on all planets, both above and below any surface.
I’m still waiting for anyone on any of these* climate blogs to try to explain the Uranus dilemma under the old radiative forcing / greenhouse effect conjecture.
It can only be explained by the new paradigm (in my paper on planetary temperatures in the PROM menu at PSI) which shows why planetary atmospheric, surface, crust, mantle and core temperatures are all able to be calculated the same way, and are all supported by the process whereby thermodynamic equilibrium evolves spontaneously, as the Second Law of Thermodynamics says it will.
* Judith Curry, JoNova, The Air Vent, PSI forum, DrRoySpencer.com (here)
“all supported by the process whereby thermodynamic equilibrium evolves spontaneously, as the Second Law of Thermodynamics says it will.”.
I agree with that except I believe it is not gravity alone that does the job. I think under the uniform radiation models I have seen explaining the gravity theory are wrong because I think the atmosphere would go isothermal under uniform radiation.
What drives the lapse rate and the resulting higher average surface temperature is the heat pump the sun represents in the presence of a revolving planet, operating like a passive solar machine driven by convection/gravity.
the nice thing about this is it answers the criticisms of physicists about the isothermal state the atmosphere would lapse into if gravity was the only variable. that makes gravity a condition necessary (creating consistency in a solar system with greenhouse gas environments) but not a condition sufficient.
In the passive solar design it is not possible to create higher than average temperatures if the ambient heat source is uniform. what you get in such an environment is the storage medium is the same average temperature as the ambient environment.
Only in a revolving planet do you get cooling at night in the ambient environment that is not matched in the better insulated medium (lower emission rate medium) thus the medium cools less and averages higher. Architects employ this technology to save energy in homes. . . .it works.
With greenhouse gases the atmosphere does cool some. One might characterize that as being lesser insulated.
So when the sun comes up what happens first is the surface must warm up then later in the morning as the surface gets warmer than the atmosphere does convection start to fill the lost heat in the atmosphere from nighttime cooling from greenhouse gases, but gas laws prevent that convection from filling all the losses.
If gases did not form pressure gradients then the atmosphere would just be plain hotter and isothermal because the greenhouse gases are less efficient emitters than the surface and the atmosphere would still operate as a heat storage warehouse. . . .just not as efficiently as a non-greenhouse atmosphere.
If you had no greenhouse gases in the atmosphere then there would be virtually no atmosphere cooling at night, no convection during the day and another means for the atmosphere to go towards isothermic.
So Roy is right, IMO, about greenhouse gases being the cause (at least in part) for the lapse rate. while I don’t believe there is anything that is completely a non-greenhouse gas, theoretically if there were the atmosphere would be blistering hot like the hottest place on the face of the moon. So we can thank greenhouse gases for cooling breezes as well.
lastly, I don’t know what our station network would record for a worldwide average temperature in a non-greenhouse atmosphere but I do know it would be a lot warmer than the radiating surface of the planet on average. . . .its really not possible to work any of this when science takes as gospel that the average radiating surface temperature is the same as the station network.
We know that day time surface temperatures get a lot hotter than the recording station temperature and at night the surface gets a lot colder.
Maybe somebody has done some work and found that in our current atmosphere those two average temperatures average the same. (but nobody seems to be able to point to even that work if it exists)
But that outcome may be happenstance created by the ability of the two mediums to warm the other. Seems unlikely though because while their radiative tradeoffs might be equal conduction and convection is not an equal two way process in a gravity field.
In architecture you collect solar radiation with radiators, transport heat into an insulated vessel that has low radiative and conductive losses to the enviroment up the gravity stream and have that heat available for raising the average temperature of the storage medium making it available for hot water for example 24/7.
You can also do it with space heating using greenhouse techologies, which as the Woods experiment showed is dependent upon restricting convection and you increase the system efficiency with double glazed fenestration.
Bottom line is I really like the work done on the gravity theory and found it thought provoking. I participated in the series of threads on WUWT that I counted over 10,000 posts. I tend to think there are elements of all the theories in the passive solar machine technology. I also think there is a good deal of uncertainty regarding change, but personally favor the idea that changes in CO2 are minor and the changes in water vapor important as it changes the lapse rate significantly and what changes water vapor remains uncertain.
sorry ..but…
you have a nice electric bulb….
you light it…
dan’t ask yourself what if i pu something close to the bulb..
just ask first
what will be the equilibrium temperature of a bulb…
then you ll come energy budget….
and you will conclude..
the temperature of an electric bulb depends on what is around!!!
the corollary is ..if you change whatever is around ..you ll chnage the equilibrium…
to be precise…
there is no reason for the temperature of a bulb to be constant at its surfaceat the equilibrium..
the general case is the opposite!
look at a radiator!!it is exactly the same thing!
so first speaking of the temperature of a bulb is wrong
even for roy plate chosen for simplicity and symetry , at the edges..the temperature is different….
thermodynamics doesn’t help much…energy budget!!!
sorry energy budget so what the surface of the object receives from any radiating object around …
Doug, I am not sure what “Uranaus dilemma” you are referring to.
ALL planets were formed with the interior much warmer than the exterior (due to the original gravitational collapse and to radioactive decay). So all planets have a gradient from warm interior to cool exterior. So of course, some level within Uranus will be 320 K. This is NOT due to “radiative forcing”.
Roy,
Every object above 0 K emits IR. The higher the temperature, the more IR is emitted. If two otherwise identical objects are at different temperatures, the one that is warmer will warm the other object more than the one that is cooler. Therefore, the plate that is across from the warmer object will cool less slowly than the plate that is across from the cooler object.
Also, for the sake of symmetry, you should either place the barrier equidistant between both plates, or alternatively place a barrier close to both plates, with a larger air gap between them.
Cheers,
Daryl
I think they will both cool at the same rate. The amount they emit depends on their temperature.
The infrared wave trying to leave the ambient plate will encounter a much larger wave coming from the hot plate which will reduce the wave coming from the hot plate and annihilate the smaller wave.
The wave leaving the cold plate will reduce the wave from the hot plate much less and the cold plate will therefor warm up quicker than the ambient plate.
“I think they will both cool at the same rate.”
You are wrong.
“The amount they emit depends on their temperature.”
True, but they also absorb energy from the hot and cold plates, so as any introductory physics textbooks will tell you, the NET amount of radiation emitted is depends on the temperature of the object AND the temperature of the surroundings.
Your last two paragraphs are a mish-mash of intuition that is partial correct and partially incorrect (or ambiguous).
The radiated heat is just electromagnetic energy and will behave as any other electromagnetic energy.
They are both contained in the same electromagnetic field.
The infrared cannot emit from the colder object or it wouldn’t heat up.
Snow at -50C
Area 1 sq metre
Emissivity 0.9
Power 126 watts
Peak emission 12.98 microns
So for a simple person like me, it’s like having 2 water tanks with a pump pumping in each direction between the tanks. The rate at which the pumps pump depends on the water level in the tanks.
One tank is almost empty and one tank is almost full.
The pump taking the water from the full tank to the empty tank will be going very fast and the pump in the opposite direction will be going very slow.
The trickle of water from the empty tank to the full tank will not increase the level in the full tank but will slow down the rate at which it is emptying.
Eventually the water levels will be equal and the pumps will be running at the same speed.
As they are reaching equilibrium the rate at which the water level in the full tank falls is getting progressively slower.
Which means the bigger the difference in temperature between the plates the faster they will cool.
I mean the faster the temperatures will equalise.
The water analogy is a good one. I tend to think of it as a dam with a flood gate. The more water(energy) the higher the flow rate. It’s always raining(background radiation) over this dam.
At equilibrium the outflow from the dam equals the rain refilling it. If the rain increases then the dam fills(temperature) and the outflow increases and vice versa for less rain.
The hot plate from the experiment is a filled dam at a higher level than normal(ambient). Placing the cold plate near it is like putting a cover over the dam that limits the rain (lower energy). Some of the outflow from the dam is fed into the cold plate(cover) allowing it to release more water(heating the cold plate)
The analogy breaks down at some point because it is an analogy.
Maybe you can get a better handle on things if you think on these terms.
The question is can the radiation from a cold body heat a hot body or will it just be reflected back.
My gut feeling is still that the plates will cool at the same rate but the hot plate next to the cold plate will cool for longer.
“The question is can the radiation from a cold body heat a hot body or will it just be reflected back.”
It is only a question in your mind because you don’t understand the Second Law of Thermodynamics and so you have invented in your mind some imaginary Second Law. In a nutshell, the Second Law is not enforced by arbitrary and capricious rules like your “reflected back” notion. The fact that the radiation emitted by a body (at any wavelength) increases with temperature and that Kirchoff’s Law of Radiation (that the absorptivity and emissivity are equal) is sufficient to guarantee that the Second Law is obeyed without coming up with convoluted enforcement mechanisms.
I have a discussion about this misunderstanding of the Second Law here: http://www.drroyspencer.com/2013/05/time-for-the-slayers-to-put-up-or-shut-up/#comment-78859 and here http://www.drroyspencer.com/2013/05/time-for-the-slayers-to-put-up-or-shut-up/#comment-78885 I give some online references that do an okay job of discussing the issue, although some modern intro physics textbooks, like Knight, Jones, and Field, “College Physics: A Strategic Approach” are probably better.
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