Ups and Downs
So Eli was slumming over at Lucia's where Steve Mosher was doing his best tipsy Richard Tol imitation and the subject was the Cruz Pause 18 year no trend in the satellite record, when a thought occurred. (Ear tip to Tamino, also look at his follow on, Drift)
If the changes in temperature over short periods (like days or months or even annually)
track each other, even just in direction in the satellite and surface
records (so) then that is pretty
convincing evidence that the problem is a long term drift in one or the
other and that on the short term they are measuring the same thing.
So Eli hit Wood for Trees and compared the RSS land only record with CRUTEM4 between 2005 and 2015. (RSS offset by 0.25 K)
If there was significant random (not actual) variation in either record, one would expect that there would be many months when the two curves moved in opposite directions. There are a few, but it's a lot like finding the panda. From this we conclude that MSU and CRUTEM4 are consistent on a monthly and even an annual basis. It might be even more interesting to look at this on a daily basis and even match times and AMSU footprint areas
Thus if (see Nick Stokes) the long term trends diverge, and the short term anomalies agree, that is pretty good evidence of systematic drift.
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The surface record analysis is simpler and a drift would require correlation between drifts at many stations using different instruments that are calibrated on site.
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Eli concludes that the drift is most likely in the AMSU satellites or the processing of the AMSU data. Unanticipated aging of the receiver or the internal hot calibration target seems to Eli most likely, although there might be something involving orbital decay (less likely now because this caused a lot of trouble early on) or even changing land/sea/ice patterns which affect the AMSU response.
Since there are four or five satellites carrying the AMSU units and there is a newer ATMS system, analysis of where the discrepancy enters would not be simple.
Posts
19 comments:
"The surface record analysis is simpler and a drift would require correlation between drifts at many stations using different instruments that are calibrated on site."
But Watts et al 2015 *have* found the surface station drift!
How soon we forget. Scratch that. How soon *you* forget. Since Watts et al's AGU poster *I* no longer subscribe to the common misperception of the surface temp data. C'mon, get with program .... it's heat sinks and microsites all the way down.
Any denialist worth his non-vaccination could tell you what is the matter with your logic. Changing "corrections" have been applied to the data. {and that is actually true for both surface and satellite date}.
It's at least possible that there is a real divergence between surface temperatures and the average over the troposphere and parts of the stratosphere measured by the satellites.
CIP is spot on, in the sense that many of the of the same denial talking points applied to the SAT can also be thrown at the TLT.
So, for example, it's hard to argue that the TLT time series are not 'homogenized' in many ways similar to the SAT time series (e. g. TOBS and the satellite diurnal correction).
Though, the real denier kicker is "I want the TLT source code" from UAH.
I am the TLT Auditor.
I'm desperately trying NOT to fall into those same types of arguments, but the 'slippery slope' of TLT trend denial is haunting me, seriously.
On another note though, I am looking at all the global indices systematically, doing some (well actually a lot of) lagged correlations between TLT and SAT (raw time series), some (well actually a lot of) FIR and IIR filtering, to visualize the temporal structural similarities and differences of TLT relative to SAT (or vice versa). Some FFT's also.
For me, at least, this all will take a while. :(
I dont think its drift. It's either the lapse rate feedback or the surface data is being tweaked by gnomes inside NOAA.
I suggest considering that the atmosphere is changing -- specifically the aerosol burden. Have you looked at India in the DSCOVR imagery? I am just guessing that the dark gray atmosphere
http://epic.gsfc.nasa.gov/epic-archive/png/epic_1b_20160112054633_00.png
(big image)
that moves around, sometimes up to the edge of the Himalayas, sometimes further south over the ocean, is burdened with coal smoke -- and that this is changing fast enough to kerfloozle someone's satellite results. There would be the same issue for the atmosphere coming from northeast China, tho' that will be imaged better in six months.
See Tamino's post for a direct comparison of RSS vs. balloon-borne (RATPAC) observations at similar altitudes, which provides fairly solid evidence that there are instrumentation issues here -- not saying for sure who's right, though I have my suspicions.
https://tamino.wordpress.com/2015/09/24/exogenous-redux/
KAP, what Eli is trying to show is the nature of the instrumentation issues. Pretty clearly, based on the data, it is a long term drift somewhere.
"It's either the lapse rate feedback or the surface data is being tweaked by gnomes inside NOAA."
FL, seriously?!
Or are you a denialist Turing test programmed to exhibit the Dunning-Kruger aspect of the Salem hypothesis?
OK, humor me a bit longer with my amateur guess. Tamino says:
"... Thermometers didn’t change how they measure temperature, nor balloons how they rise through the atmosphere. But satellite instruments have gone through many changes, satellite orbits have altered, and the satellites themselves change over time. I strongly suspect that there’s a serious problem with the satellite data after about the year 2000, as indicated by their divergence from thermometer data...."
Asking again, hoping someone knows -- did the atmosphere change, particularly locally? I look at the DSCOVR imagery showing that dark gray cloud moving around north and eastward from India, day after day.
And I wonder -- are balloon data being taken from that area?
If not, it'd be the satellites that would be looking down on that dark gray cloud -- would they get a different result incorporating that in a global result, than the balloon data would?
I dunno. Maybe weather balloon coverage is thoroughly understood but not by me.
Over the past 15 years, how has the atmosphere changed there?
The difference between 5.6 and 6 has to do with the fact that UAH USED to do this — “UAH does not yet correct the diurnal drift for satellites carrying Advanced Microwave Sounding Units because they attempt to use these satellites during periods when the diurnal drift is small.”
http://www.theguardian.com/environment/climate-consensus-97-per-cent/2015/mar/25/one-satellite-data-set-is-underestimating-global-warming
Now they are using a diurnal drift correction – but this got them closer to the RSS than to the CRUtemp…
So there is something affecting the diurnal drift, if eliminating it effectively gets rid of the problem.
respectfully
bjchip
...and yes... it could be that it affects the diurnal drift near the black clouds coming out of India and China... and the 5.6 data from UAH is telling us how much of it is a difference in location... ? OK... I'm done. No more speculation.
I'm going to wait for Eli and Tamino and Nick Stokes to get together with Po-Chedley to do a paper that clearly needs doing.
Eli,
I you visit the UAH page
http://nsstc.uah.edu/climate/
and download the December 2015 Global Temperature Report, you will notice that there is a list of the top 5 warmest years according to UAH data. On the same UAH page is a link entitled "Monthly Average Data".
If you calculate the average temperatures using this data you will find that although the order of hottest 3 years is the same, the orders of the fourth ad fifth are not. Moreover the anomalies are different.
Something odd is going on!
Might be the change over from 5.6 to 6.0 in their algorithm??
Eli,
The data at the UAH website is 5.6. The report seems to be using the unpublished 6.0beta4 data that is only available from Roy Spencer's website.
So, CIP, EFS, on the one hand, you seem to have bought into the idea that climate disruption remedies should not be pursued until there is observational evidence in the series "proving" impact of CO2 upon climate. On the other, you seem to throw every conceivable doubt-regarding-methodology into the path of observational vehicles for assessing climate measurements which yield a result other than warming. How do you justify this?
If I or someone were to throw a bunch of these observational vehicles into a blind bag and pick them for assessment, independent of what they say, would not you accept their results? Seriously, the posterior distribution of the outcome of an estimate of warming should not be conditional upon the range of that warming. It should be independent of it. Don't you agree? And if you do not, why not? And if you pretend to be rational, what are these other things you condition on?
And what if the prediction of warming does not depend, primarily, upon observational evidence, but, rather, come from physical theory?
bobo2016,
Beta6 and older versions can all be accessed from this page at UAH. 't2lt' for 5.6, and the other is easily seen.
Last I swear it thought on this:
http://aqicn.org/map/
air quality index maps for various continents
Forgot to link the link bobo2016:
http://vortex.nsstc.uah.edu/data/msu/
[Beta6 and older versions can all be accessed from this page at UAH. 't2lt' for 5.6, and the other is easily seen.]
Niptickery: "Nick Stoke's Moyhu" in the sidebar
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