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.
Wren:
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.
I doubt the trends are the same on both sides of your house. Do you think the trend on the sunny side stays the same depending on the clouds? I would think cloudy days vs sunny days would change the trend from the sunny side to the shaded side.
how I love those trends:
http://www.dmi.dk/dmi/index/klima/klimaet_indtil_nu/temperaturen_i_groenland.htm
http://met.no/?module=Articles;action=Article.publicShow;ID=882
http://www.junkscience.com/MSU_Temps/Greenlandan.html
http://www.junkscience.com/MSU_Temps/Arctic75Nan.html
It is utterly naive to elaborate about how is it that they consider or not this or that data. They are absolutely involved in LYING, in doing the “TRICK” their bosses have asked them to demonstrate the earth is on fire, so they can start their speculative business of buying and selling “carbon shares”, this time building up a financial bubble gigantic in size with no assests or stocks behind whatsoever but pure vacuum.
Steve, can you do a comparison by latitude band (perhaps 5o intervals)? That would be more informative than using different southern and northern latitude bands in your graphs between the different data sets. That way you can see if any one of the data sets you analyze has a bias relative to another one. I’m pretty sure if a scientist published a paper comparing these data sets when they don’t have the same latitude ranges, you would critique their analysis rather harshly. Also, make sure that the data are on the same grid before doing this analysis and that you area weight the results.
Extrapolation is not a bad thing, it is a best guess that’s all.
In mathematics one can interpolate and extrapolate on multi variables.
Interpolation is used in a data set with missing series data inside the curve, ie the data set finite.
Extrapolation however is a hoary beast untamed, because it is not within the cage. One should not let that beast run too free.
It seems to me that the trend in the GISS-UAH difference is very close to zero during the time period that you show. And what would a HadCruT vs UAH plot look like? It really seems that GISS is actually much closer from UAH than the other guy. Which supports the idea that GISS is actually covering more efficiently the Arctic zone.
BTW, Artic extent is now lower than in 2007.
Steve/Anthony, when are you going to mention the Arctic sea ice? It has dropped below 2007 and is at the previous record for this time of year set in 2006. Why are you remaining so quiet about this? Can you do a post as to why this is occurring?
stevengoddard says:
May 20, 2010 at 6:51 am
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.
=====
Sounds like a lot of work. It makes me tired just thinking about it.
Since the UAH and RSS Arctic temperature data are very accessible, I will repeat my suggestion that you compare their trends, as they may not be in total agreement. In your third chart the difference between the UAH and GISS temperatures are the same (0.6) in 1997 and 2009, while in your second chart the difference between RSS and GISS temperatures are 0.4 in 1997 and 1.0 in 2009. It looks like UAH and GISS are showing about the same Arctic temperature change over the 1997-2009 period, but RSS is not.
Khrisna Gans asked: “…who and what is Steve(n), Stephen Goddard, please ?”
Where is the response that addresses that question?????
…Regarding the Death Valley parking lot near the weather station… Overstating one’s
case…no?? My old joke about the English temp record E of London was due to Green-peace placing 4 black Mercedes around that WS isn’t perhaps so farfetched… (Aug 2003)
PS. Death Valley… they’re really trying hard to beat Libya in 1922, September…That
might have been some sort of heat-burst??…or extreme foehn?? DS.
@ur momisugly abraxas
I’ll probably tell what you don’t want to hear, but there are many here that don’t give much credence to peer-reviewed articles. Mostly because the system of publication has been hi-jacked by the alarmists. The e-mails clearly show their manipulation of the science journals. So, as a result, I don’t know which studies to point you towards, given “peer reviewed” carries little meaning or weight with me. Drs. Spencer and Christy are well published, you can start there. Dr. Pielke is also as is Dr. Lindzen. The all have a list of publications link on their homepage, except, I can’t find Spencer’s.
I would leave you with this token piece of advice. They’ve sent you on a fools errand. They’re asking you to disprove a negative. A nearly impossible task. The onus isn’t incumbent on you or anyone else to disprove the CAGW fantasy, the onus is squarely on the alarmists to prove their musings.
Best wishes.
There is nothing for it but to put out an independent permanent array of self recording temp stations in the arctic and temporary stations on the ice after freeze-up. Is there an independent non-political benefactor out there who could bankroll such a project – hey lets go crazy and stud Africa with them too instead of extrapolating from Cairo to Lagos to Johannesburg to estimate the Congo temp. This will give the real, non-synthetic temps and will also allow a test of the 1200 km extrapolations. Why is this such a problem. The arctic is crawling with scientific clones – can’t they carry a bunch of thermometers along with them? Do they simply want to bore holes in the ice and tsk tsk about the unprecidented (not very scientific measure) conditions. They just finished a two year arctic frolic with their icebreakers and floating laboratories and all we get out of this billion-dollar exotic holiday is a rehash of preconceived conclusions that are awfully light on hard numbers.
One has to be very suspecting of ever rising numbers since the high of 1998 from GISS who are trying their best to create a new world temp record while HADCRUT shows declining temps (was this after the climate shakeup or were they always showing this decline?). I think we will see the GISS numbers bend down a bit after the current climate bishops step down.
While I am very suspicious of the idea that GISS’s extrapolation technique can work, I must comment that this comparison is not fair, as stated above the coverage of the data sets is different. Might I suggest using Climate Explorer to look at the data in the latitude bands where data exist for all data sets?
And if one wants to compare GISS very high latitudes with an alternative data set…we could go back quite a long way with this:
http://ocean.dmi.dk/arctic/meant80n.uk.php
stevengoddard says:
May 20, 2010 at 7:21 am
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.”
_______________
Two points:
1) The Arctic is a more homogenous climate regime than we would see when comparing Denver, CO to Death Valley. It is not just the distance, but the local climate differences. You would expect Death Valley and Denver to be different and have greater variations.
2) I do not dispute that GISS may (or may not) be inflating data, but the argument is spurious from the perspective that temps ARE going up, and the region’s climate seems to be changing. How much they are going up, with a few tenths of a degree here or there is not important when talking about several degrees change. It seems the point of even bringing it up would seem to be to raise doubt about significant temperature changes in the Arctic. I find this possibly deceptive and spurious at least…
R. Gates says:
May 20, 2010 at 7:04 am
“GISS data extrapolation techniques are well within the bounds acceptable scientific technique”
————–
This is a ludicrous statement.
“R. Gates says:
May 20, 2010 at 7:04 am
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.”
Please learn that there is more than one organization estimating arctic ice extent. Nansen shows it “normal” for 2 month now and practically at the 2009 level, clearly higher than 2007 and 2008. Your scientific credentials might improve if you mention what you are citing, a good practice in any case.
Data from DMI: http://data.ecmwf.int/
http://ocean.dmi.dk/arctic/meant80n.uk.php
Calculation of the Arctic Mean Temperature
The daily mean temperature of the Arctic area north of the 80th northern parallel is estimated from the average of the 00z and 12z analysis for all model grid points inside that area. The ERA40 reanalysis data set from ECMWF, has been applied to calculate daily mean temperatures for the period from 1958 to 2002, from 2002 to 2006 data from the global NWP model T511 is used and from 2006 to present the T799 model data are used.
The ERA40 reanalysis data, has been applied to calculation of daily climate values that are plotted along with the daily analysis values in all plots. The data used to determine climate values is the full ERA40 data set, from 1958 to 2002.
http://data.ecmwf.int/
1200km squares, eh?
It’s a glorious day in Central England: 22C. For convenience can we declare the temperature in southern Iceland to be 22C?
speculates:
Geomagnetic field affects the polar gyres (circular currents), currents regulate the climate. No need for thermometers, just measure the magnetic filed (by airlines over-flying the pole).
http://www.vukcevic.talktalk.net/LFC16.htm
http://www.vukcevic.talktalk.net/NFC1.htm
http://www.vukcevic.talktalk.net/NFC3.htm
abraxas says:
May 20, 2010 at 6:04 am
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?
How about this site then.
http://www.populartechnology.net/2009/10/peer-reviewed-papers-supporting.html
vukcevic speculates:
Geomagnetic field affects the polar gyres (circular currents), currents regulate the climate. No need for thermometers, just measure the magnetic filed (by airlines over-flying the pole).
http://www.vukcevic.talktalk.net/LFC16.htm
http://www.vukcevic.talktalk.net/NFC1.htm
http://www.vukcevic.talktalk.net/NFC3.htm
Craig Moore says:
May 20, 2010 at 8:05 am
Khrisna Gans asked: “…who and what is Steve(n), Stephen Goddard, please ?”
Where is the response that addresses that question?????
In another thread, stevengoddard stated he wasn’t the same guy in the publications.
Interestingly when E M Smith did his analysis of Eurika’s temperature history it does not show very much warming at all.
http://chiefio.wordpress.com/2010/04/23/eureka-canada-graphs/
How does false extrapolation cause warming? I view these datasets as works of fiction on several grounds; lack of coverage, lack of consistency in siting and equipment, willingness to arbitrarily adjust temperature upwards, lack of UHI correction, willingness to remove inconvenient stations, lies, lies, lies, etc. But the fact that the arctic isn’t covered well should not produce any more bias than is already present. I’m not sure you’ve uncovered what is going on.