You assume the two should be equal and that is your error. “Calculation of the Arctic Mean Temperature So, I had to add a consevative value for 2010 as 10-12 days where missing, and so everything points to that i have underestimated this years cold in the Arctic 80N-90N – i will update in weeks time. Their official SST dataset is made up of HADISST from Jan 1880 to Nov 1981 and Reynolds OI.v2 SST data from December 1981 to present. “Although Bob Tisdale has made many valid criticisms of Frank’s procedures..” But my graph shows a trend 1991 – 2010 that most certainly is not prematurely illustrated. K.R. However …. The GISTEMP land surface dataset that GISS identifies as dTs is a carry over from an old paper in which GISS attempted to reproduce global surface temperature without using SST data, because the SST data was so sparse in the 1980s. Frank’s post is about the discrepancy between DMI and GISS. The newly available (2009) and updated high resolution ERA Interim re-analysis gives even higher trend values between 70-90N of around 1.0 degrees C/decade over the twenty year 1989 to 2010 period at the surface, where warming has been shown to be strongest (see Screen and Simmonds 2010). And in Hansen et al (2010) they also confirm their official SST dataset. Comments Policy... You need to be logged in to post a comment. HadISST1+OISST will continue to be our standard product unless and until verifications show ERSST+OISST to be superior.”
It appears that the overall seasonal cycle is riding on a gradually warming average value, but peak positive excursions are being limited by the ice melt temperature in Summer. But reality is: These data actually seems to be part of reality – dont you agree? On the other hand, the Reynolds OI.v2 SST data is only available in the satellite era, from Nov 1981 to present. Bob, I too have considered that ERA-40 data ends in 2002 and this might be part of the explanation. http://i33.tinypic.com/2wgt92d.jpg But Michael, please go through my site: http://www.hidethedecline.eu and see if “franks procedures” generally have a problem before you just write like this. Its true, its a typo, it should have been “Hadley/Reynolds” as this is the data I show and use. In a recent comment, I posted the co-located temperature data link for camera #1. camera #2, PAWS, the one on your ice page, is at: Certainly, one could choose -1.9 degrees as a cutoff, but the meaning and conclusion of the data is not changed: Average Arctic summer temperatures at 80 deg north have fallen consistenly and steadily since 1958 while CO2 levels have steadily increased.
K.R. Your assumption is incorrect. (In this case, the records are for those days when the avaerage temperature since 1958 has been greater than 0.0 C. Convenient enough cutoff date for our purposes. Refer to page 26. http://hidethedecline.eu/media/ArcticGISS/fig5.jpg K.R. Temperature, Pressure, etc.
Frankly I would not expect a lot of change (extent) at 80N and 90N, it is after all at the melt centre, be it fighting a losing battle. Despite this, the DMI data has been used as a reference for comparison. This, I suppose, begets the idea of the necessity of responsible leadership. The additional step was to further smooth the figures by using an unweighted rolling 5 year average.
Is it basically a convincing idea to use land/city/Airport temperatures for temperatures at sea? Not really, but I would prefer if you stopped for a moment and actually considered what implications the warmer winters have. However, the melting of the ice does not take place evenly, it mainly takes place at the edges of the ice cap. Quick question: won’t the latent heat of melting ice tend to pull down the air temperatures? When i alowed my self to put a conservative value for 2010 its because the rest of the melting season should behave like a natural disaster + an atomic bomb to really change things radically now Data above this latitude is considered unreliable, and is not available. http://hidethedecline.eu/pages/posts/the-perplexing-temperature-data-published-1974-84-and-recent-temperature-data-180.php
marek says: And that’s another important point, as my synthetic data illustration displays, the number of melting days is very important. This pattern is likely to prevail whilst substantial permanent sea ice remains above 80N. August 5, 2010 at 2:47 pm HadCRUT3 uses a similar gridded format to GISS, but a different methodology which does not include extrapolated Arctic grid cell values. The entire basis for the original hypothesis is, in other words, false. I’ll then redirect my comment to you. I just focus on the areas where both SST and GISS land temperatures for oceans are available to make it easier to see how huge the differences are.” Many other articles have attempted to compare Arctic trends derived from satellite based microwave sensors with surface based (such as GISS) Arctic values, highlighting apparent differences. (Except, of course, for summer.) But there is basically no difference between the GISS12o0km radius smoothing and the source Reynolds OI.v2. NASA, June 3, 2010. Petter Nikula says: 2) What was the exact methodology used to produce the graphed values? Care is also advised in the use of MSU data at high latitudes due to MSU sensor scanning geometry, for example the standard zonal “polar” data from RSS covers from 60N to 82.5N.
Another interesting insight:
” to me it seem quite irrelevant, because all it shows is surface temperatures above ice ranging between 1.25C and .04C. Arctic weather Surface Pressure and 2 meter air temperature over sea ice and ocean, North of 60 ° N. Data are based on analysis data from the global operational weather forecasting model at ECMWFs.The model analysis can be considered to be a 0-hours forecast, and is the best estimate of the current state of the atmospheric system and it is based on available observations and the model physics.
GISS added the ERSST.v3b SST data to their mapmaking webpage back in February. THE ESCALATOR Well , on checking the north pole web cam , which I have been assured by a member of the camera crew is correct , it is showing the cameras temperature is 11 centigrade … 2) What was the exact methodology used to produce the graphed values? Already by now my consevative value of 0,5K is too high. Once the ice melts, continued additions of energy will then warm the water. Comments Policy... You need to be logged in to post a comment.
Link to this page. So if this is not interesting, then you are saying that DMI is presenting data wrongly? “So we can all make mistakes, we should just help each other in a good way, motivate each rather than the opposite.” Climate Change Science Program on changes in the Arctic and at high latitudes. (i.e. This is one reason why GISS does not currently use SST data in the seasonal ice region above 75N, even when this data is seasonally available, - as is increasingly the case due to diminishing trends in ice extent, and better coverage due to satellite data. http://wattsupwiththat.com/2010/07/28/giss-arctic-vs-dmi-arctic-differences-in-method/#comment-442773. If the data from each global data set is gridded over approximately equal Arctic areas then the differences reduce to well within the error bars of the data. Comparing the results with GISS over the same grid area over dates where the recent ice station and buoy data is used, the correlation is just as high. Please, stop measuring temperatures during the melt season! So the whole point of the article was hard to find for me and it really confused me a long time. Sorry for the confusion on my part.
The green line above is the DMI temperature average, a little over 0,9 Celsius). Offline PDF Version | Fuzzylogic19 says:
Thank you for your question and interest in our website! In the areas where the dTs data extends out over the oceans, do you have any proof that is not extrapolated and interpolated correctly from the land surface data? The Danish Meteorological Institute (DMI) Arctic 2m air temperature data.
Is that optimal for a scientific thinking person simply to have wrong information? What does the global shift in diets mean for climate change? Direct comparisons of measurements from surface based sensors and remote sensors like the more recent Moderate Resolution Imaging Spectroradiometer (MODIS) on the TERRA and AQUA satellite platforms show that cloud cover can bias infra red Arctic surface temperature measurements low, for example see Hall 2004 on MODIS Sea Ice Surface Temperature, Scambos 2006 on validation of AVHRR and MODIS ice surface temperature, Randriamampianina 2009 on assimilating ATOVs data in Polar regions, and Koenig 2010 on MODIS data compared with high accuracy surface-based thermochron sensor data on Greenland). DMI don’t produce this data.
Identical argument for the end point of the melt season. anthony holmes says: And the more ice melts the cooler the environment will be. Method: its described earlier in the comments – i think i will add it to the article. What is considered the start of the melt season? Political, off-topic or ad hominem comments will be deleted. It’s good to see this DMI trend plotted: The data flatly contradicts completely Hansen’s mythical +4 degree Arctic temperature “rise” over the past few years. What about the other observation based data sets, and other independent satellite data?