NOAA/NCDC recently
announced that July 2009 set a new record high global sea surface temperature (SST) for the month of July, just edging out July 1998. This would be quite significant since July 1998 was very warm due to a strong El Nino, whereas last month (July, 2009) is just heading into an El Nino which has hardly gotten rolling yet.
If July was indeed a record, one might wonder if we are about to see a string of record warm months if a moderate or strong El Nino does sustain itself, with that natural warming being piled on top of the manmade global warming that the "scientific consensus" is so fond of.
I started out looking at the satellite microwave SSTs from the AMSR-E instrument on NASA's Aqua satellite. Even though those data only extend back to 2002, I though it would provide a sanity check. My last post described a significant discrepancy I found between the NOAA/NCDC "ERSST" trend and the satellite microwave SST trend (from the AMSR-E instrument on Aqua) over the last 7 years...but with the AMSR-E giving a much warmer July 2009 anomaly than the NCDC claimed existed!
The discrepancy was so large that my sanity-check turned into me going a little insane trying to figure it out.
So, since we have another satellite dataset with a longer record that would allow a direct comparison between 1998 and 2009, I decided to analyze the full record from the TRMM Microwave Imager (TMI). The TRMM satellite covers the latitudes between 40N and 40S, so a small amount of N. Hemisphere ocean is being missed, and a large chunk of the ocean around Antarctica will be missed as well. But since my analysis of the ERSST and AMSR-E SST data suggested the discrepancy between them was actually between these latitudes as well, I decided that the results should give a pretty good independent check on the NOAA numbers. All of the original data that went into the averaging came from the Remote Sensing Systems (RSS) website, (
Link). Anomalies were computed about the mean annual cycle from data over the whole period of record.