This surprised me – not only the little warming step of 0.2°C in UAH but the difference gets markedly noisier after 2005.
In Australian data the warming step is much more marked and looks a year or so later.
This surprised me – not only the little warming step of 0.2°C in UAH but the difference gets markedly noisier after 2005.
In Australian data the warming step is much more marked and looks a year or so later.
These differences appear to coincide roughly with the start of the use of NOAA-18 in both datasets. I’ve examined the US region and as I recall RSS looks very odd there. I have an interesting argument that UAH is probably correct, and the US station based data probably correct, but the *global* surface temperature data has a warming bias relative to UAH- *especially* when you account for the different variability of each.
One of the most interesting, and therefore ignored, questions in climate science is, why are surface temperatures diverging from troposphere temperatures?
Answer = reduced clouds, especially low level aerosol seeded clouds + some urbanization warming
As I recall, RSS and UAH are to some extend calibrated against surface temps. The step change may result from different changes in the respective calibration algorithms to better reflect the divergence.
Why is the step change larger in Aus?
I’d say our network has more urban and airport bias than the USA.
The increased noisiness may be a seasonal effect. I noticed that in the last few years UAH has a pronounced seasonal divergence in the anomaly some years but not others.