By Steven Goddard
GISS has explained their steeper temperature slope since 1998 vs. Had-Crut, as being due to the fact that they are willing to extrapolate 1200 km across the Arctic into regions where they may have no data – whereas Had-Crut prefers to work with regions of the Arctic where they actually have thermometers. WUWT reader “Wren” suggested that I compare GISS Arctic trends vs other sources to see how they compare. GISS has been showing Arctic temperatures rising very fast, as seen below.
However, GISS Arctic temperatures have been rising much faster than other data sources. The graph below shows the difference between GISS and RSS (GISS minus RSS) Arctic temperatures.
And the same graph for UAH.
Conclusions: GISS explains their increases vs. Had Crut as being due to their Arctic coverage. Their Arctic coverage is poor, and they rely on extrapolations across large distances with no data. Comparisons with other data sources show that GISS extrapolations across the Arctic are likely too high. In short, GISS trends over the last decade are most likely based on faulty extrapolations in the Arctic, and are probably not reliable indicators of global or Arctic temperature trends during that time period.
Ya know…who cares about thermometers, this is about big money and cheat all those serious scientists out there who will discuss everyday, in their “skeptic” blogs, about our latest “findings”!
Hope they won´t dedicate their time to investigate our real activities and secret relations. We are the forebearers of the future, the initiates who are building the world of the future, the brilliant “Alphas” who will govern upon those silly “gammas”.
(Chances are that these self nominated “alphas” are being cheated by their bosses and will be discarded as useless once they achieve their goal)
Commenter, “Think Big”, on a http://www.smh.com.au weblog, is unimpressed with you Steven, esp with your Venus thread here at WUWT. I think I know why. Think Big went to univercity.
O/T TOTALLY:
I need to ask for some assitance please.
http://www.thoughtleader.co.za/mikebaillie/2010/05/18/dear-denialists-i-must-apologise/
After this article i was asked to:
“..supply peer reviewed publications that do not support the ACC hypothesis …”
Now i referred them here, but here does not include peer reviewed literature against the global warming argument.
Where on earth could i send them?
Thank you kindly 🙂
A quote from GISS about surface temperature:
Q. If SATs cannot be measured, how are SAT maps created ?
A. This can only be done with the help of computer models, the same models that are used to create the daily weather forecasts. We may start out the model with the few observed data that are available and fill in the rest with guesses (also called extrapolations) and then let the model run long enough so that the initial guesses no longer matter, but not too long in order to avoid that the inaccuracies of the model become relevant. This may be done starting from conditions from many years, so that the average (called a ‘climatology’) hopefully represents a typical map for the particular month or day of the year.
I interpret that as WAG! Some might claim SWAG! Or even EWAG!
extrapolation is a neat trick when the data has some logical progression.
but the existing data needs to be concrete. sort of like opposite shores of a bridge being built, a little error at the start and the two extrapolated ends of the bridge don’t meet out over the chasm.
since time frame is of some importance in creating a weather extrapolation, one would need to know that the data over time has not become contaminated by ANYTHING. Unless you can assure that point you are peeing on my leg.
As was mentioned earlier the most recognized scientific term for the GISS method is: GIGO!
Henry chance
The extrapolations are unrelated to 1998 temperatures. Please read
http://wattsupwiththat.com/2010/05/18/gistemp-vs-hadcrut/
Well, it should also be noted, if I am reading these maps right, that HadCrut doesn’t actually guess at the arctic temperature beyond it’s measurable reach whereas we regularly see GISS maps taking the temperature measurement of it’s few stations and plastering them across the entire region.
Wren says: May 20, 2010 at 5:09 am
I’m not sure I would agree with the “likely” and “probably” on the basis of the limited analysis presented. It’s a start, but all sources of Arctic data should be examined and compared, and if they aren’t measuring the same thing, the emphasis should be on comparing difference in anomalies.
Don’t you get it, there is no Arctic data, it’s all an extrapolation/guess. What adjectives would you like to describe a WAG?
All one need do is read up on Polyakov’s Arctic research to discover Hansen’s methods are not supported by any observational data or experimentation, but is rather based on his own untested assumptions.
Part of that assumption is stratospheric cooling due to CO2 which has no basis in fact.
Another is assuming a correlation of Arctic amplification to global warming also due to rising CO2 levels, which Polyakov cautions against as the data do not support.
Patrick Davis
It is pretty obvious that temperatures on Venus would be much lower without the very high pressure atmosphere. Might take a while for it to sink in though.
NASA GISS’s misprepresentation of GCM extrapolations as measured Arctic temperatures, and their subsequent use in anomaly graphics, is inconsistent with Hansen’s own view of the McIntyre/Watts corrections to the contiguous US temperature record a few years ago. Hansen suggested that, since the US land surface is such a small portion of the global surface area, temperature trends in the US make little to no difference to the global picture. Surely this reasoning applies in spades in the Arctic.
It seems like the best solution to the Arctic conundrum of data paucity is to simply truncate the global surface temperature anomaly maps where the surface station readings stop. At the same time, change over to a map projection that presents a more realistic image of the global surface, rather than the current projection that balloons the Arctic and Antarctic regions. Its pretty ironic/convenient/sad that the current projection has maximum distortion precisely in the regions where the temperature trends are least understood. But of course, that can work in your favor when pushing a political agenda.
blackswhitewash.com says:
May 20, 2010 at 3:25 am
Both datasets are dubious. Basically we have no real proof that the Arctic is actually warming at all in reality.
So, the ice cover retreating, increased melting of Greenland, permafrost thawing, the tree line moving further north, the E. Siberian Shelf showing more methane release all are no proof of the Arctic warming? You may want to tell that to the people living in the Arctic…
Wren at 5:09 am
I see your point and agree up to your last point wherein you said:
…and if they aren’t measuring the same thing, the emphasis should be on comparing difference in anomalies.
There I disagree. If they aren’t measuring the same thing – difference in anomalies are – meaningless. Don’t forget, in ALL this we are dealing with averages, of averages, of averages. To come up with a difference (the anomaly) between averages means nothing (it’s not even actually an “anomaly”) even if it’s averaging the same data set at a different point in time, much less 2-3 averages from 2-3 different data sets derived from 2-3 very dissimilar – locations, instruments, times, total data points, etc., etc.
Now “trend” differences between multiple averages taken over a LONG period of time whose multiple data sets have been triple verified for accuracy in all manners – – hmm, MAYBE one could derive some meaning +/- from that analysis.
Steve Keohane says:
May 20, 2010 at 6:22 am
Wren says: May 20, 2010 at 5:09 am
I’m not sure I would agree with the “likely” and “probably” on the basis of the limited analysis presented. It’s a start, but all sources of Arctic data should be examined and compared, and if they aren’t measuring the same thing, the emphasis should be on comparing difference in anomalies.
Don’t you get it, there is no Arctic data, it’s all an extrapolation/guess. What adjectives would you like to describe a WAG?
====
No Arctic data? None from RSS, UAH, DMI, and NSIDC ? Good heavens, are you suggesting Steve just made up numbers? I want to hear his side of the story.
Wren
The UAH and RSS Arctic temperature data is very accessible. I doubt NSIDC has their own database, and I am not sure how to access DMI’s database.
Steve, does this mean you believe in the Had-Crut data set now?
chris y
Excellent points. The Arctic is not very big, has almost no data, and Hansen is using it to justify the polarity of his trend over the last decade.
EnviroCanada assures me that they have 37 surface stations to WMO/GCN standards in the Canadian arctic (above 66N) and the data is available on line.
For some reason GISS only appears to use data from only one of these stations (Eureka) on a continuous basis and two others (Alert and Resolute) from time to time.
According to the IEA, the situation in Russia is similar but I have not yet verified this claim in detail.
Given the huge areas involved in Russia and Canada how can one justify the practice of ignoring most of the thermometers?
The more I think about the argument, the less I am convinced.
Whatever one thinks about GISS extrapolating over the pole:
since UAH and RSS don’t cover the pole, but cover additional, lower latitudes, IMHO one can not conclude from differences between GISS and UAH/RSS that GISS extrapolations are too high.
It would be interesting to compare the difference in trends based solely on 65°-80°, 65°-82.5° and 65°-85°. If differences were decreasing / increasing with coverage, as seems to be the case if one looks at the RSS and UAH graphs, wouldn’t that be a hint that the GISS extrapolation is likely ok / too high?
Steve,
I find your argument quite hollow and tending to nit-pick over data. To dispute the rise in arctic temperatures over the past few decades leaves me suspicious that you are not being completely neutral in your observations. GISS data extrapolation techniques are well within the bounds acceptable scientific technique, and the areas not covered, even if they (in some extremely unusual phenomenon) had cooler temps than extrapolated, the areas that are covered are so high, that the arctic would still show warming. In short, your argument is specious at best, and I await your next Arctic Sea Ice update, as temps remain high in the arctic region (as they’ve been for the whole winter and spring) and the extent for 2010 year-to-year data has now fallen below 2007, 2008, 2009, 2005, & 2003. Just a “statisical” fluke, I’m sure, but it seems your mult-year ice is not holding up quite as well as you’d thought…
“stevengoddard says:
May 20, 2010 at 6:30 am
Patrick Davis
It is pretty obvious that temperatures on Venus would be much lower without the very high pressure atmosphere. Might take a while for it to sink in though.”
Now you are taking the (Nuh Zilund speak) puss, roit aye! I mean, some stuff on another, totally alien planet, it totally different on our planet. ~90x atmospheres, that’s like home right? Some people just don’t get it!
stevengoddard says:
May 20, 2010 at 5:38 am
Bob,
Your tinypics confirm my point. GISS had no data north of 80N, and Had Crut did.
And RSS and UAH have no data north of 82.5ºN.
The large area included in the RSS and UAH south of 64ºN which is not included in GISS covers a huge land area, whereas 64ºN covers little land. So in order to do a proper comparison you should at least have the same southern boundary.
R. Gates
You live less than 1200 km from Death Valley. Can Hansen tell the temperature at your house using a thermometer in Death Valley? LOL “acceptable scientific technique.”
REPLY: Specifically, this USHCN thermometer used in GISS? – Anthony
more here
Milwaukee Bob says:
May 20, 2010 at 6:36 am
Wren at 5:09 am
I see your point and agree up to your last point wherein you said:
…and if they aren’t measuring the same thing, the emphasis should be on comparing difference in anomalies.
There I disagree. If they aren’t measuring the same thing – difference in anomalies are – meaningless. Don’t forget, in ALL this we are dealing with averages, of averages, of averages. To come up with a difference (the anomaly) between averages means nothing (it’s not even actually an “anomaly”) even if it’s averaging the same data set at a different point in time, much less 2-3 averages from 2-3 different data sets derived from 2-3 very dissimilar – locations, instruments, times, total data points, etc., etc.
Now “trend” differences between multiple averages taken over a LONG period of time whose multiple data sets have been triple verified for accuracy in all manners – – hmm, MAYBE one could derive some meaning +/- from that analysis.
—————-
I agree that differences in anomalies can be meaningless if the same things aren’t being measured, but not necessarily. The temperature probably is different on the sunny and shady sides of my house, but the trends should be the same. So if similar things are being measured, we may be able to do meaningful comparisons of their anomalies.