Blog Memo to James Hansen Regarding GISS Southern Hemisphere Land Surface Temperature Data
James, you should look into this matter. I don’t have the time or the inclination to carry this investigation any further.
Some persons might think GISS has been manipulating data to acquire a higher land surface temperature anomaly trend in recent years. They also might assume GISS has been reducing coverage in recent years to create a little more variability, thereby increasing the chances for new record temperatures with each El Niño. And the way that all suppliers of temperature data appear to use data for a grid one year but not the next, and then have data for that grid reappear a year or two later, may lead some persons to think data is being cherry picked for use. We wouldn’t want people to think those things.
Final note: As you know, GISS, in effect, deletes sea surface temperature data in areas of seasonal sea ice and replaces it with much-more-variable land surface temperature data. This, of course, creates a warming bias at the poles in the GISS data. Refer to the zonal-mean graph in Figure 11 that compares the linear trends of the Reynolds OI.v2 data and the version of it with the GISS modifications, for the period of January 1982 to October 2011. It’s from my most recent post that discusses this subject: The Impact of GISS Replacing Sea Surface Temperature Data With Land Surface Temperature Data.
Because of that monumental bias, when I present GISS Land-Ocean Temperature Index data, I usually limit the latitudes to exclude polar data. Now, with this find in your land surface temperature data, I’ve had to switch to an average of the GHCN and CRUTEM3 data for that chapter of Who Turned on the Heat? The Unsuspected Global Warming Culprit, El Niño-Southern Oscillation.Sorry to say, but with all of the biases toward warming, your GISS LOTI data, in my eyes, is becoming more and more unsuitable for research.
much more
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