Firstly for 1950-2004 there seems to be a very good agreement with Lisa's map thru 2003 except Aiguo has Australia, Africa, S America and other areas also filled in. However for 1979-2004 there are major differences with the Vose one from NCDC. South America still has negative trends in the Dai work vs positive for Vose. The US, Australia and Europe have distinctly more negative trends in Dai: the sign changes in many points. In Spain it goes the other way? There seems to be some agreement at some islands where presumably the data are limited and more likely similar: Hawaii, Bermuda, near Madagascar,?? The lack of reproducibility here is very disturbing. Lisa can weigh in on which, if any is closest to hers. Comments? Suggestions? Kevin [Trenberth]
Kevin Trenberth wrote:
Hi all I am sufficiently concerned about this that I have asked Aiguo Dai to use his data to compute DTR trends for 1979 to 2004. Aiguo has all the synops and so values are based on a much more comprehensive dataset with wider coverage, including oceans, but perhaps with problems and inhomogeneities such as ASOS. Still it will be a useful sanity check. Kevin Phil Jones wrote:
Kevin, Byron, Agree that we will have to wait till Russ gets back to check this out. Added Russ in on this reply. Russ sent Fig 3.2.2 for the ZOD, which we still have in the FOD figure at the moment. We will need this updating. Presumably the new one will be similar to one from the ZOD. That figure had a trend of -0.08 C/decade for 1950-2003. From a guesstimate of the trend over 1979-2003 in this figure, the trend is about -0.2 C in total. This sort of trend is in the first light blue category, just less than -0.1 C/decade. I reckon that the average of the trends in the 79-04 map would average to about this number. So, it seems OK. I am though a little alarmed at how variable the trends are between adjacent boxes. [Phil Jones]
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