Tuesday, July 21, 2015

NOAA up 0.02°C in June; GISS now up 0.04°C

I don't normally post separately for the NOAA NCEI global temperature anomaly index, but this month is the first where everyone is using the new V4 ERSST. There is also a revision of GISS post-V4 (thanks to GISS for the acknowledgement). So it is an opportunity too to review how well TempLS matches in the new environment.

The NOAA report has June at 0.88°C relative to 20Cen; up from 0.86°C in May. GISS is now 0.8°C, up from 0.76°C. Both these are the hottest June in the respective records, and would be close to the hottest month ever, if it were not for Feb-Mar of this year. I have described in my GISS post where it was hot and cold, with more quantitative information here; the NOAA report presents a similar account in more detail.

I have noted earlier how, as expected, TempLS mesh and GISS tend to go together, being interpolated, and NOAA and TempLS grid also have an affinity. Indeed, at times, TempLS and NOAA have been eerily close. With V4 that has been somewhat interrupted, although the general pattern still holds, and the correspondence is currently close. I'll show plots below the fold.

Incidentally, the revised GISS now shows nothing unexpected in the plot of recent monthly differences (earlier version here). Here how it looks now:

So here is the plot over 4 years of NOAA vs TempLS grid. The plots are made using this gadget, and are set to a common anomaly base of 1981-2010. The divergence earlier this year is the largest. Otherwise the correspondence is good.

And here is the comparison of TempLS mesh with GISS. I think the correspondence is better than before the ERSST change.

And here is the combined plot. I've used reddish for grid, bluish for interpolated. You can see the pairing, although they are all fairly close. The pairs come together at the end; this is just how it happened.


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