GISS Divergence with satellite temperatures since the start of 2003

GISS Divergence with satellite temperatures since the start of 2003

From Watts Up withThat, January 18, 2009

By Steve Goddard and Anthony Watts

Some of the excellent readers of the last piece we posted on WUWT gave me an idea, which we are following up on here.  The exercise here is to compare GISS and satellite data (UAH and RSS) since the start of 2003, and then propose one possible source of divergence between the GISS and satellite data.  The reason that the start of 2003 was chosen, is because satellite data shows a rapid decline in temperatures starting then, and GISS data does not.  The only exception to the downward trend was an El Nino at the start of 2007, which caused a short but steep spike.  Remembering back a couple of years, Dr. Hansen had in fact suggested that El Nino might turn into a “Super El Nino” which would cause 2007 to be the “hottest year ever.”

The last six years ( 2003-2008 ) show a steep temperature drop in the satellite record, which is not present in the GISS data.   Prior to 2003, the three trends were all close enough to be considered reasonably consistent, but over the last six years is when a large divergence has become very apparent both visually and mathematically.

Click link for larger source image http://www.woodfortrees.org

Since the beginning of 2003, RSS has been dropping at 3.60C/century, UAH has been dropping at 2.84C/century, and GISS has been dropping at 0.96C/century.  All calculations are done in a Google Spreadsheet here:

The divergence between GISS and RSS is shown below.  Since the start of 2003, GISS has been diverging from RSS at 2.64C/century, and GISS has been diverging from UAH at 1.87C/century.  RSS has been diverging from UAH at minus 0.76C/century, indicating that RSS temperatures have been falling a little faster than UAH over the last six years, as can also be seen in the graph above.

Read the rest here