By Steve Goddard
There has been an active discussion going on about the validity of GISS interpolations. This post compares GISS Arctic interpolation vs. DMI measured/modeled data.
All data uses a baseline of 1958-2002.
The first map shows GISS June 2010 anomalies smoothed to 1200 km. The green line marks 80N latitude. Note that GISS shows essentially the entire region north of 80N up to four degrees above normal.
The next map is the same, but with 250 km smoothing. As you can see, GISS has little or no data north of 80N.
Now let’s compare the GISS 1200 km interpolation with the DMI data for June 2010.
Daily mean temperatures for the Arctic area north of the 80th northern parallel, plotted with daily climate values calculated from the period 1958-2002.
http://ocean.dmi.dk/arctic/meant80n.uk.php
DMI shows essentially the entire month of June below the 1958-2002 mean. GISS shows it far above the the 1958-2002 mean. Yet GISS has no data north of 80N.
Conclusion : GISS Arctic interpolations are way off the mark. If they report a record global temperature by 0.01 degrees this year, this ↑↑↑↑↑↑↑ is why.
——————————————————————
Straight from the horse’s mouth.
the 12-month running mean global temperature in the GISS analysis has reached a new record in 2010…. GISS analysis yields 2005 as the warmest calendar year, while
the HadCRUT analysis has 1998 as the warmest year. The main factor is our inclusion of estimated temperature change for the Arctic region.
– James Hansen
In other words, the GISS record high is based on incorrect, fabricated data. Why did Hansen apparently choose to ignore the DMI data when “estimating” Arctic temperatures? GISS Arctic anomalies are high by as much as 4 degrees, and yet he claims a global record measured in hundredths of a degree. As Penn and Teller would say …. well I guess I can’t say that here.
stevengoddard says:
July 29, 2010 at 11:01 pm
Phil,
Which of course is true, as Julienne and Gavin Schmidt have both pointed out.
What has actually been pointed out? You said “It is thermodynamically impossible to have summer anomalies of +2-4C in the region above 80N”. I would agree with Phil on this though perhaps not for the same reason . An anomaly is dependnat on the baseline average. I’ve looked at one or two of the few 80+deg N stations in the GISS database and it’s clear that 2+ deg summer (JJA) anomalies are possible and do happen, so it’s quite likely that 2+ deg anomalies happen for a single month as happened in this case. I’d also like to remind you that it is not the entire region that had a 2+ anomaly – only about a quarter of it.
The 1958-2002 GISS anomaly for the region above 80N is ~1.3 deg. Do we know what the DMI anomaly is and do we know how the 1958-2002 baseline averages compare.
stevengoddard says:
July 29, 2010 at 11:01 pm
Phil,
Which of course is true, as Julienne and Gavin Schmidt have both pointed out.
I doubt that very much, for example there’s no reason why you can’t have such an anomaly over open water north of 80ºN, or equally above the inversion layer. As I said such a generalization is unjustifiable.
Steve, you have sucked them in. They’ve taken the bait hook, line, and sinker (I think the hook is set deep in their lower intestine). The AGW fools are arguing what “could” be (based on their models and extrapolations), without making a single attempt at collecting verifiable data. I especially like the fact that you’ve got one of the bigger fish on the line, Julienne. Not a troll, but a true believer. They desperately need the arctic ice to melt! Too bad the PDO had to reverse, and we face a solar grand minimum. They are completely distracted from whats transpiring in the SH. Again, too bad!
Steve ~
For what it’s worth, I fired off an email to COI, asking if your comparison – and conclusion (“DMI shows essentially the entire month of June below the 1958-2002 mean. GISS shows it far above the the 1958-2002 mean. Yet GISS has no data north of 80N.
Conclusion : GISS Arctic interpolations are way off the mark.“) is valid.
The response, from Gorm Dybkjær at COI/DMI was as follows:
“Based on the ‘GISS’ and the ‘+80north’ data only – there is absolutely no justification for that conclusion! As already stated in the blog – the values are not considering the same geographical area. Moreover – as you can read in the attached text – the ‘+80north’ data are biased towards the pole-area temperatures, hence even further away from the area of the ‘GISS’ data. Finally, a cold anomaly in the +80N area is not unlikely to occur even though a warm anomaly is present further south. ”
“The GISS data are observations and the ‘+80north’ values are modeled values. However – the modeled values are based on all available observations (ground-, radiosonde-, airplane- and satellite- measurements) – so in one way or the other, both values are based on observations. “
The attached text he refers to was:
“The ‘plus 80 North mean temperature’ graphs are based on model ‘analysis’ data from a range of global models from the European Centre for Medium-Range Weather Forecasts (ECMWF). The model ‘analysis’ is the best guess of the initial state of the atmosphere and surface (prior to the actual forecast runs), based on all available observation and the physical constrains of the model.
The ‘plus 80 North mean temperature’ plot are the mean temperature for ALL model grid-points from the 00z and 12z analysis of the applied model. Since the model grid-points are distributed in a regular 0.5 degree grid, the mean temperature values are strongly biased towards the temperature in the most northern part of the Arctic! Therefore, do NOT use this measure as an actual physical mean temperature of the arctic. The ‘plus 80 North mean temperature’ graphs can be used for comparing one year to an other and for comparison to the climate line – in the same plot.
The data from 1958-2002 are ERA40 reanalysis data and the data from 2002 till now, are obtained from the operational model at the given times! The climate curve is calculated from from the full ERA40 period, 195709-200208. You can find information of the models on the ECMWF web pages (www.ecmwf.int).”