November Global Temperature Update Delayed

December 9th, 2011 by Roy W. Spencer, Ph. D.

There has been a delay in our monthly processing of global temperature data from AMSU.

An undersea telecommunications cable used to transmit about half of the huge volume of data coming from the Aqua satellite was cut in late November off the coast of the Netherlands, delaying receipt of that data. While there were redundant data transmission capabilities, apparently both failed.

Also, John Christy and I have been on separate travels quite a bit lately (I spent 2 weeks in Miami after my daughter had an emergency C-section — I’m a grandpa!) and now I’m at the AGU in San Francisco, with a trip to DC early next week, so monitoring of the situation has been difficult.

Version 6 of the UAH Dataset is in the Works

I have been working on a new diurnal drift correction for the UAH global temperature dataset, which will be released as Version 6 when it is finished.

The orbital drift of most of the satellites carrying the AMSUs (and earlier MSUs) has been the largest source of uncertainty in getting long-term satellite temperature trends, and the correction for this drift has been a research topic for us off-and-on for many years.

Fortunately, there has always been at least one satellite operating without significant drift, and so we have used those satellites as a “backbone”, or anchor, for the others. The Aqua satellite is the only one which has its orbit maintained with on-board propulsion, but channel 5 on the Aqua AMSU instrument has become increasingly noisy in recent years, so we anticipate at some point we will no longer be able to rely on it, thus the need for a new diurnal drift adjustment.

I’m hopeful that the new procedure I’ve developed will work well, which is rather novel and is mostly insensitive to instrument calibration (see if you can figure out how that would work, wink-wink). The ultimate test will be the removal of long-term drift between simultaneously operating satellites, which also depends on season. It should allow us to get better regional temperature trends, land-vs-ocean trends, and remove some spurious season-dependent differences in temperature trends.

The earliest Version 6 of the UAH dataset would be available is the early January update of the December temperature data.

Comments are closed.