Having compensated surface temperature data for el Niño, volcanic aerosols, and solar fluctuations, it’s appropriate I should do the same for satellite temperature data. After all, upper atmosphere temperature (what the satellites estimate) responds to these factors much more strongly than the surface temperature, so it can be argued that it’s more important to compensate satellite data than surface data. Not doing so can cause some very misleading conclusions about temperature trends.
I’ll use the lower-troposphere data (TLT) from RSS (Remote Sensing Systems) and UAH (Univ. of Alabama at Huntsville, v5.6). Here’s the data from RSS, together with the model incorporating all three exogenous factors:
Just as with surface temperature data, the match is impressive, and demonstrates that the extreme high temperature during 1998 is just about entirely due to the el Niño. The same is true for UAH data:
After removing the estimated influence of el Niño, volcanic activity, and solar fluctuations, we have a much better picture of what the satellite data are saying about the part of temperature change due to human influence. Here’s the corrected data (annual averages, UAH in blue, RSS in red) compared to the surface temperature data from NASA (in black):
It’s surprising how well they all agree, until after 2011 when RSS diverges and after 2013 when UAH begins to diverge. A more direct comparison is available by subtracting the surface temperature data (from NASA) from the satellite data. Here’s UAH data minus the NASA data:
Here’s RSS data minus the NASA data:
The big difference between RSS and NASA is the declining RSS temperature after 2011, but there’s also distinct sign of a consistent decline from 2000 onward.
To compare the two primary satellite data sets, here’s RSS data minus UAH data:
Again there’s a distinct sign of decline in RSS (relative to UAH) after 2000, with RSS warming more rapidly than UAH pre-2000 and less rapidly post-2000.
Readers are invited to draw their own conclusions from the foregoing. But one conclusion is blatantly obvious from the corrected data: that claims of “no warming since 1997” or “no warming since 1998” based on satellite data are wrong. The false impression is a direct consequence of the impact of el Niño; once that confounding influence is removed, it’s easy to see how silly those ideas are. Unless, of course, you’re a republican running for president like Ted Cruz.
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