Last night I read “Argo and the Ocean Temperature Maximum” by Willis Eisenbach at “Watts Up With That?”. The post shows that ocean surface temperature usually reaches a maximum of 30 degrees C, and very seldom goes beyond this point. This prompted me to look at the latest ARGO ocean temperature data, which confirmed what Eisenbach wrote.
But this morning I recalled having seen NASA maps which showed sea surface temperatures exceeding 30 degrees C. These maps have always puzzled me, because about 40 years ago I worked on a project measuring ocean temperatures, and I had never seen anything exceeding 30 degrees C either. So I decided to look up the NASA maps to see what they showed. Interestingly, they have a map here
This site shows ocean temperatures exceeding 30 degrees C all over the place. The map legend says it´s May 2001 data obtained using MODIS1.
Because this NASA map looks so spooky, I decided to check the color palette they used to show ocean temperature (I copied and pasted a simple scale). Then I cut and pasted the 30 to 31 degrees C color palette range onto the Indian ocean, an area NASA shows was way above 31 degrees in May 2001:
Edited NASA map. I included a numerical temperature
range on top of the color legend, then copied the 30 to 31
degree C square on the Indian Ocean to confirm NASA´s map
showed large ocean areas exceeding 31 degrees C.
To confirm the NASA data was quite goofy I looked up a series of ARGO buoy data sets (from October 2014). None of the buoys showed temperatures exceeding 30 degrees C. I also looked up a temperature trend graph for a square sector which covers a piece of Western India and the Indian Ocean region near the coast. The historical data doesn´t show much of a temperature change since May 2001. So I pasted the whole thing together, so you can have a look at it by yourselves:
Map showing Indian ocean sector which NASA´s map showed
with temperatures above 31 degrees C (May 2001). A single
ARGO data set for October 2014 shows temperature is below
30 degrees C. The Hadley Center temperature record shows
temperatures haven´t changed much since 2001.
After playing around with this material this morning I´m starting to think NASA uses color blind employees to prepare the temperature maps they load on their webpages. My recommendation would be for NASA to test their employees for color blindness before they are assigned to prepare and review this data for public use.
1 MODIS description from the referenced webpage: “MODIS is sensitive to five different wavelengths, or "channels," of radiation used for measuring SST. Both night and day, the sensor measures the thermal infrared energy escaping the atmosphere at 12 microns and then compares that measurement to how much energy is escaping at 11 microns, allowing scientists to determine how much the atmosphere modifies the signal so they can "correct" the data to more accurately derive SST. The MODIS sensor, because of the increased number of channels, tells us a great deal about the influence of the atmosphere on measurements of SST. Similar to AVHRR, MODIS also takes daily measurement of the global ocean.”