Saturday, June 4, 2016

May SST down 0.03°C

I have been describing a new Moyhu index made by integrating the NOAA gridded sea surface temperature ERSST V4. I have added it to the data on the latest data page. You can find on the monthly table, where it currently sits with the secondary sets, and the new value is right down in the bottom right corner after scrolling. This table is getting unwieldy, and I'm going to reorganise. You can also find it in the updated active graph. The big virtue of ERSST is that it is released early in the following month, and it is now out for May. There will be a revised version later in the month.

I'll show plots below the jump. SST has been settling gradually following the El Nino, and in May, the ERSST index dropped from 0.411 to 0.383°C, on an anomaly base of 1981-2010.

So first, here is a snapshot of the active plot. It shows a comparison with NOAA ocean, and HADSST3. It is very close to the NOAA index, as one would expect. It is integrating the same data, so the differences (which I have been working to reduce) are methodological.

To show how close I have been able to get to the NOAA index historically, here is a plot of the two going back to 1961, with differences. As mentioned in my earlier post, I think the differences are primarily in treatment of sea ice, and the later NOAA index uses information not currently available for May 2016. Also the agreement shown is between the values as they now are in the dataset; the values first posted are revised late in the month.

The ERSST index will be available in the trend viewer after the next run ( a few hours hence). Soon I'll show some regional divisions (NH, SH, Tropic etc).


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