Dr Fred Singer’s, SEPP Science Editorial (copied below) #1-09 (1/3/09) in “The Week That Was” (TWTW), address’s the issue of the difference between University of Alabama in Huntsville (UAH) [Christy and Norris, 2006] and Remote Sensing Systems (RSS) (Mears and Wentz 2005) MSU lower troposphere (LT) temperature data[1979-2007].

Dr Singer refers to the Heartland Institute publication which he edited, “Nature Not Human Activity Rules the Climate”, where Fig’s 9a and 9b seen below, indicate the effect of the hypothetical correction that is required in the RSS data. In a nutshell, the red squares should plot further to the right to agree closer with the blue squares.

The RSS MSU_LT anomalies show a greater warming trend 1979-2008 than do UAH and the majority wisdom around the pro-IPCC Blogosphere is that RSS are correct and UAH wrong.There is also published peer-reviewed evidence that a cooling correction to RSS is required. Randall and Herman Jan 2008 say in their abstract:

“..Diurnal correction signatures still exist in the RSS LT time series and are likely affecting the long-term trend with a warm bias.”

There is more in their paper which I do not have.

The Douglass and Christy paper (Accepted by Energy and Environment Aug 2008) “Limits on CO2 Climate Forcing from Recent Temperature Data of Earth” has an Appendix A. “Comparison of MSU and RSS” where the authors address the issue and conclude that there is a positive jump of 0.136 degrees K in RSS at about 1993, when two satellites briefly overlapped.

I agree with Dr Singer that this is indeed a significant correction that is required in RSS LT MSU.

SEPP Science Editorial #1-09 (1/3/09)John Christy and Roy Spencer (Univ of Alabama, Huntsville (UAH) pioneered the methodology of extracting climatologically useful atmospheric temperature data from the satellite microwave sounding unit (MSU) instrument, a great achievement, since the instrument was not designed for this purpose.

The analysis requires many kinds of corrections. A competing group, RSS, pointed to one correction that the UAH group had overlooked: the influence of a slight decrease in satellite altitude due to orbit decay [1998]. UAH immediately made this correction — a small change in the analysis algorithm. It increased the temperature trend slightly — although it is still much smaller than the surface trend.

But the RSS trend, based on an independent analysis of the same basic satellite readings, continued to show a larger, more positive trend than UAH, with the independent balloon data supporting UAH. This discrepancy between RSS and UAH became a hot topic — which has persisted. Neither group, both very competent, could pinpoint the exact cause.

In Dec 2002, at a CCSP workshop in Arlington ,VA, I heard a full presentation of the RSS results by Carl Mears. I noticed that the RSS temp record showed a small ‘jump’ around 1993, where a transition occurred between two satellites, with only a short overlap in time. I then e-mailed Mears and Spencer (and a few others), and suggested a comparison of RSS and UAH trends before and after 1993, to see if that might be the origin of the discrepancy. It’s really an obvious idea; I was not prepared (or capable) to dig into the detailed analyses of the two groups to isolate the actual cause.

Such a comparison has just been performed by Douglass and Christy (my co-authors in a 2007 paper) in an appendix to a paper on climate sensitivity (published in Energy & Environment, Aug 2008). As I had expected, in support of the UAH result, they now find agreement between RSS and UAH trends — although I will hold up until Carl Mears confirms this result.

Apparently, Douglass & Christy do not consider their finding of great importance. I beg to differ. To see why, pls look at Figs 9a and 9b in the NIPCC report “Nature Not Human Activity Rules the Climate” www.sepp.org/publications/NIPCC_final.pdf — and move the RSS point to coincide with UAH.

Disagreement between greenhouse models and observed trends now becomes quite obvious and strengthens the NIPCC conclusion that Nature, not human activity, rules the climate.