Friday, June 19, 2015

New NOAA - record May anomaly

NOAA has a new version, based on the new ERSST4. This has prompted me to make a change in the NOAA data that I use. They publish two sets; I have been using MLOST, which is the traditional one based on 1961-90 anomalies. But they also publish a version based on 1901-2000, and this is what they use for their climate summary announcements. Updates to MLOST have been lagging, so it is time to change. The different basis shouldn't affect the usual plots on the latest data page, or the trendviewer, but will affect the tabulated numbers.

So the May number was considerably higher than the previous May, and as I expected, higher than April, unlike GISS. In fact, it was quite in line with the NCEP/NCAR index.

I see there is a post at WUWT suggesting that the new record is somehow an artefact of the new version. As I commented here, the versions differ very little in year to year changes, by month. It is very unlikely that the old version would not have shown a similar rise, and in both versions, May 2014 was hotter than any previous May.


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