What are the absolute temperatures for the base periods for each of NASA's GISS, HadCRUT3, and UAH?

Well, I already know NASA's, at least the number they cite is 14.0藲C.





I'm having trouble finding HadCRUT3's absolute temperature, since they simply state "relative to 1961-1990 base period" and refer to a study from 2006, which I skimmed through but couldn't see any reference within dealing with an absolute temperature.





Then again, it wasn't a thorough skim.





And then of course there's UAH.








I'm trying to compile a single graph which I can upload to Flickr that contains all of the monthly data from each set, on the same scale, and a mean of the sets offset for clarity. I understand how to do each, I just need to know what the absolute temperatures are for the base periods. Thanks ahead of time, I might not be spending much more time on here this night.|||I couldn't find them either, but Wood for Trees both plots them together and provides their offsets:



"Here are the means for 1979-1999 for each source, to 2 decimal places:



Source Mean

HADCRUT3 0.15

GISTEMP 0.24

UAH 0.00

RSS 0.00 "



*edit* the Wood for Trees method is an easy way to do it. Just take the average of whatever time period you're plotting for each data set, and subtract it off.|||There are no absolute values per-se and that鈥檚 because different methodologies produce different results. Instead the anomalous values are expressed against a single representative value and in this respect the GISTemp and HadCRUT records both use 14.0掳C. I don鈥檛 know, but I would guess that the UAH / RSS base figure would be similar, and quite likely the same. I doubt if the NCDC has a value that they use.





The calculation of an absolute base figure essentially takes a number of climatologies and calculates an average of those. The CRU for example uses鈥?br>




鈥?Land north of 60掳N


鈥?Land south of 60掳S


鈥?Ocean north of 60掳N


鈥?Ocean south of 60掳S


鈥?Land and ocean between 60掳N and 60掳S





The currently used value of 14.0掳C was the result of research conducted in 1999 by Jones, New, Parker, Martin and Rigor. Prior to this a value of 14.1掳C had been used, this having been derived from research conducted by Taljaard, VanLoon, Cuutcher and Jenne in the southern hemisphere and by Crutcher and Meserve in the northern hemisphere during 1969 and 1970.





This isn鈥檛 particularly satisfactory when wishing to express temperatures against an absolute value (which would only really be absolute in K or R). It鈥檚 not something anyone has ever really given a great deal of thought to as it鈥檚 not something that is needed.





Ultimately, we have something or an arbitrary base figure against which the anomalies are expressed. Given that the anomalies are expressed against a fixed value, they themselves will be accurate but the conversion into an absolute temperature won鈥檛 be as accurate. Different sources use different margins of error for doing this of between 0.1掳C and 0.5掳C.