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101 conspiracy theories about troposphere temperature: the RSS love affair is over
Sou | 10:48 PM
Over at WUWT there have been three articles about the lower troposphere temperatures. The first (archived here) was a Guest Post by Werner Brozek and Nick Stokes, Edited by Just The Facts with the title: "Long Satellite Pauses Ending (Now Includes January Data)". The second article was about the February data for UAH (archived here, latest here). It had the wistful wishful title: "Global Temperature Report: Warmest Ever February 2016 driven by El Niño". The third article is the real doozy (archived here). It's by Anthony Watts so could well have some awful blunders in it. He's called his article: "The ‘Karlization’ of global temperature continues – this time RSS makes a massive upwards adjustment."
This article is a few hours late, and I'm not satisfied that I've got everything right because this is a subject on which I am feeling distinctly out of depth. Science deniers will try to tell you that there are little thermometers on satellites sending raw data to Earth and miraculously drawing temperature charts - or something like that. That's a pile of hogwash. The real story is much more complicated. Satellites come and go. Instruments change. Orbits decay. Temperature isn't measured directly, it's estimated from measurements from microwave sounding instruments (MSUs). What's reported is the result of complex calculations after adjustments and conversion to temperature. What we get are temperature trends in very thick layers in the atmosphere (kilometers thick, looking upwards into space), not the temperature of a particular spot or distinct level in the sky. Then there is "diurnal drift" - which is largely what the new paper by Carl Mears and Frank J. Wentz is all about.
Warning: this article is rather long. It explains the new RSS paper in more detail than I did in the previous article.
The lower troposphere "Pause" is officially dead
The first article was written ahead of the release of UAH and RSS data, and was in part about how the so-called "pause" will end in either February or March, depending on whether the February anomaly is 0.88 C or higher for RSS or 0.315 or higher for UAH. It was. For both. So the RSS and UAH "pauses" are officially ended, if you take WUWT to be anything like official.
The February temperature record was driven by more than El Niño
Despite the headline that the UAH February record was "driven by El Niño", the second article had this to say (my emphasis):
By a statistically significant amount, February 2016 was the warmest month in the satellite temperature record, according to Dr. John Christy, director of the Earth System Science Center at The University of Alabama in Huntsville. Interestingly, however, that record might have as much to do with an extraordinarily warm month in the Arctic as it does with warming caused by the El Niño Pacific Ocean warming event.Which is what was pointed out here at HW - and here.
Anthony Watts jumps up and down and sez the new RSS paper has a fatal flaw
The third article shows just how sensitive Anthony Watts is to any hint that the world really is getting hotter. He jumps on something Roy Spencer said to him, but unlike Roy, Anthony decides it means there's a "fatal flaw" in the new RSS paper. As if Anthony Watts would know!
Anthony began his article once again falsely accusing the NOAA scientists of fraud. Anthony Watts is just another wacky conspiracy nutter of the lizard men kind. He wrote:
Forget homogenization, that is so 2010. If the pause is bothering you and your belief is that there must be more warming, we only need to find it in the data, then what you need is “Karlization”, named after director of the National Climatic Data Center, (now NCEI) Tom Karl who pulled a fast one this summer trying to adjust the past down, so the present would be warmer. The sleight of hand on this was so obvious that even warm-oriented scientists such as Michael Mann and Ben Santer co-authored a rebuttal paper that said Karl was dead wrong and the pause was real. There is now a congressional investigation into Mr. Karl’s apparently political actions disguised as science.
Of course no scientists wrote anything about Karl15 being "dead wrong" or a "pause" being real in the sense that global warming stopped. Anthony is talking through his hat. ( This is what he's referring to, and Graham Readfearn has a terrific article at the Guardian about it, too.)
And does Anthony Watts know that of all the main four temperature datasets, NOAA has the lowest warming trend for the period since 1971? The 1970s was the last time the trend changed, according to research published in Cahill15. Does Anthony Watts know that the trends per decade differ in only the second decimal place - by 0.01 or by 0.001 if you want to talk annual trend? Here are the trends from the different datasets from 1971 to 2015:
Anthony Watts has been trying to get sued for defamation for years now. He might succeed one of these days. (RSS isn't a government agency so Carl Mears could sue if he thought it worth his while.) Anthony's specialties include lying about science (as above), falsely defaming scientists (as above), looking stupid (as in Russian steampipes), acting in a cowardly fashion ( slinking away from U Bristol), and being unethical.
Having set the scene, Anthony wrote about Dr Mears:
Clearly, he’s miffed. So what to do? Taking a cue from the other Karl, he publishes a paper and claims that new and improved adjustments have “found” that missing warming.
He has falsely accused the NOAA scientists of fraud, so by taking this stance he is also effectively accusing Carl Meares and Frank J. Wentz of fraud.
How does RSS v4 differ from v3.3?
Before getting into Anthony's so-called "fatal flaw", I'll try to set out how the new version 4 of RSS mid-troposphere temperature differs from v3.3. Early in their paper, Mears and Wentz explain how they have to remove the diurnally-varying component from observations to derive the long term trend in temperature.
The derivation of long-term trends in tropospheric temperature from satellite observations requires that the diurnally varying component for the observation be removed. This is because the local observation time for most of the satellites drifts over time ( Christy et al. 2000; Mears and Wentz 2005), causing diurnal variations to be aliased into the long-term record.They describe how this has been done by them previously (in v3.3) and by others:
- In previous RSS versions, they constructed a climatology using a general circulation model. NOAA's STAR used the same approach.
- UAH in version 5.6 used "cross-scan differences" to work out the "local diurnal slope"
They report how Po-Chedley et al showed that none of the models completely remove the effects of the diurnal cycle, and this new paper of Mears and Wentz confirms that finding. Instead of using a general circulation model, they have adopted "an harmonic method" for removing biases relating to satellite diurnal drift. This method is based on analysis of the satellite observations themselves. The authors explored three approaches, all of which gave similar results for AMSU data:
- MIN-DRIFT - where they exclude parts of each satellite record during times of rapid drift in observation time. They couldn't adopt this approach holus bolus (a technical term) because it wouldn't work for MSU data in the early part of the record.
- REF-SAT - where they use two satellites that didn't drift (AQUA and METOP-A) as reference satellites to adjust the drifting satellites. Again, that only works with the period in which those satellites were operational, and couldn't be applied to the earlier part of the record.
- DIUR-OPT - where they adjusted GCM-derived diurnal cycles (ie from general circulation models, I presume) using information got from comparing satellite observations at different local times. This can be applied to the entire record and is the one that Mears and Wentz used for v4.
Oh it's all very technical. I expect some HW readers will understand it. However I'm not even a novice when it comes to satellites and microwave sensors and correcting for diurnal drift and I don't understand a lot of it, so if you can't follow any of this, blame me.
Anthony Watts issues a plea for help from denier scientists
Now Anthony Watts wouldn't know the difference between a satellite and a weather station any more than he can tell an anomaly from a baseline. So just in case his message didn't get through to Christopher Monckton (who has adopted the RSS dataset as the "gold standard" of temperature datasets), he sent a hasty missive to Roy Spencer and John Christy to see if they could find fault with the paper. Well, they'd barely had time to read it. In fact they may have just looked at the pictures without reading the text, because Roy wrote back fairly promptly. Just getting an email from Roy Spencer was sufficient for Anthony to proclaim a "fatal flaw":
Dr. Roy Spencer and Dr. John Christy have already looked into this latest “Karlization” and have found what appears to be a fatal flaw. It's fairly obvious that Anthony didn't understand the paper or Roy's email or what the so-called "fatal flaw" might be. He added no comment other than "Yes, yes it does", which was wise, knowing Anthony as we do. He just put up a picture from the new paper. Roy wrote back saying:
The paper is for MT, not LT…but I think we can assume that changes in one will be reflected in the other when Mears completes their analysis.That's what I figured, too. So that part was okay, because I agree :) (However it suggests that Anthony got the wrong end of the stick and mistakenly thought the paper was about lower troposphere data.) It's the next bit that got Anthony Watts all excited.
Roy Spencer thinks he's found a problem - but has he?...
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