"We had been concerned that the LT temperature trends over land were too warm compared to the ocean. One hint that something might be wrong was that the trends over very high elevation portions of the Greenland ice sheet and the Himalayas were much colder than the surrounding regions (see Fig. 4 here). Another was discontinuities in the trend patterns between land and ocean, especially in the tropics.(Emphasis mine.) Changing model parameters by hand to eyeball it towards a predetermined goal? What the hell....?
"We determined this is most likely due to a residual mismatch between the MSU channel 2 weighting function altitude on the early satellites versus the AMSU channel 5 weighting function altitude on the later satellites. We already knew AMSU5 peaks lower than MSU2, and had chosen Earth incidence angles in each to get a match based upon theory. But apparently the theory has some error, which we find equates to about 150 meters in altitude. This was enough to cause the issues we see….land too warm at low elevations, too cold for elevated ice surfaces.
“We therefore changed the AMSU5 reference Earth incidence angle (from 35.0 to 38.3 deg.) so that the trends over Greenland and the Himalayas were in much better agreement with the surrounding areas.”
Wednesday, February 03, 2016
Those Arbitrary Changes to UAH's Model
Am I really the only one who is stunned by what Roy Spencer wrote on his blog yesterday?
Posted by David Appell at 2/03/2016 09:20:00 PM