Satellite Battle: RSS vs UAH

It's not exactly Star Wars but it's sort-of-a-big-deal anyway. RSS vs UAH: take your pick. I'm on the UAH team.

[h=2]Satellite battle: Five reasons UAH is different (better) to the RSS global temperature estimates[/h]
And so the adjustments war ramps up a notch.
There are two main groups that use essentially the same NASA and NOAA satellites to estimate global temperatures. In the last year, they’ve both made adjustments, one down, and one up, getting further apart in their estimates. In ClimateWorld this is a big deal. Believers are excited that now a satellite set agrees a bit better with the maligned “hot” surface thermometers. But UAH still agrees more with millions of weather balloons. The debate continues. Here’s my short synopsis of the Roy Spencer (and John Christy) from the “Comments on the new RSS lower tropospheric temperature set.” (If something is wrong here, blame me).
[h=4]The Bottom Line:[/h]1. Both data-sets show far less warming than what climate models estimate. UAH shows +0.12 C/decade, the new RSS trend is up to +0.17 C/decade. But climate models estimate +0.27 C/decade in the lower troposphere.
2. The headline suggesting that the RSS revisions found “140% faster warming since 1998” is the usual hype. The warming trend was tiny to start with. The headlines didn’t tell us that RSS is now warming a few hundreds of a degree per decade faster, because “who cares”?
[h=3]Five reasons UAH is different to RSS[/h]

1. UAH agrees with millions of calibrated weather balloons released around the world. RSS now agrees more with surface data from equipment placed near airports, concrete, airconditioners and which is itself wildly adjusted.
2. In the latest adjustments UAH uses empirical comparisons from satellites that aren’t affected by diurnal drift to estimate the errors of those that are. RSS starts with model estimates instead.
3. Two particular satellites disagree with each other (NOAA-14 and 15). The UAH team remove the one they think is incorrect. RSS keeps both inconsistent measurements.
4. Diurnal drift probably created artificial warming in the RSS set prior to 2002, but created artificial cooling after that. The new version of RSS keeps the warming error before 2002, but fixes the error after then. The upshot is a warmer overall trend.
5. UAH uses a more advanced method with three channels. RSS is still using the original method Roy Spencer and JohnChristy developed with only one channel (which is viewed from three angles).

[h=3]The Future — more good data will be adjusted to match bad data[/h]In January Roy Spencer predicted that RSS would be revised upwards, that he and John Christy would not be asked to review the paper (despite them being the longest running experts in this area), it would sail through peer review quickly, and would have multiple authors. Roy was right on almost all of that. h/t to Tony Heller at RealClimateScience.
Roy now predicts that the radiosondes will be adjusted to “agree” with the RSS version. This pattern of good data series being adjusted to agree with bad ones is a continuation of what happened to surface thermometers, where the worst sites are not removed from the series, but used to adjust the better sites.
All these points have finer details, which I’ll try to summarize below, but Roy Spencer’s blog is the place to read it all.
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I have never been a fan of trying to decipher high resolution temperatures from satellites. There are too many variables that is simply impossible to properly account for.

Jack Hays said:

It's not exactly Star Wars but it's sort-of-a-big-deal anyway. RSS vs UAH: take your pick. I'm on the UAH team.

Click to expand...

Whereas for years, you were literally posting at least one thread per month championing the RSS data because at the time that was the one which showed what you wanted to see, while UAH version 5 was in close agreement with the surface records :roll:

I suspect that more objective individuals will not see this as an issue to "take your pick" on: Different methodologies - and in the case of surface vs. satellite records, different altitudes - often produce different results. But one interesting point these substantial differences between satellite methodologies highlights is the contrast to how similar the results of the surface temperature records are despite their differing methods. It has always been fallacious to directly compare the surface and satellite records (since they measure such different altitudes), but this does seem to further confirm that the uncertainties of the former, while still substantial, are smaller than the uncertainties of the satellite analyses.

It should also be noted that while Nova wants to portray this as a UAH/RSS 1v1, the reality is that there are more than two satellite reconstructions available, and between UAH version 6, RSS version 4 and NOAA's STAR version 4, it is UAH which is the outlier (from Santer et al 2017):

Mithrae said:

Whereas for years, you were literally posting at least one thread per month championing the RSS data because at the time that was the one which showed what you wanted to see, while UAH version 5 was in close agreement with the surface records :roll:

I suspect that more objective individuals will not see this as an issue to "take your pick" on: Different methodologies - and in the case of surface vs. satellite records, different altitudes - often produce different results. But one interesting point these substantial differences between satellite methodologies highlights is the contrast to how similar the results of the surface temperature records are despite their differing methods. It has always been fallacious to directly compare the surface and satellite records (since they measure such different altitudes), but this does seem to further confirm that the uncertainties of the former, while still substantial, are smaller than the uncertainties of the satellite analyses.

It should also be noted that while Nova wants to portray this as a UAH/RSS 1v1, the reality is that there are more than two satellite reconstructions available, and between UAH version 6, RSS version 4 and NOAA's STAR version 4, it is UAH which is the outlier (from Santer et al 2017):

Click to expand...

Roy Spencer:

“Comments on the new RSS lower tropospheric temperature set.”