Wednesday, June 10, 2020

May global surface TempLS down 0.17°C from April.

The TempLS mesh anomaly (1961-90 base) was 0.844deg;C in May vs 1.014°C in April. This drop was larger the fall in the NCEP/NCAR reanalysis base index, which was 0.064°C. ERA5 showed a near-identical fall of 0.07 °C. By contrast again, the UAH satellite data for the lower troposphere showed a rise of 0.16°C.

Other reports on the reanalysis emphasised that despite the fall from April, it was still the warmest May in the record. That is true for TEmpLS too (just); May 2016 anomaly was 0.825°C.

The most prominent feature is again a very warm N Siberia, extending into the Arctic. By contrast N America except for the Pacific coast, and Eastern Europe were cool.

Last month I commented on the timing of posting, noting that now a lot of GHCN V4 data becomes available very promptly, and then there is a trickle of late data, which can sometimes have an outsize effect on the result. That creates a dilemma about whether to wait. That month the late data did not make much difference. This month the flow of data has been similar; we have 8599 stations to date, but there may be 1000 more to come, eventually. There has been little new data in the last three days. So we'll see.

Here is the temperature map, using the LOESS-based map of anomalies.

As always, the 3D globe map gives better detail.

This post is part of a series that has now run since 2011. The TempLS mesh data is reported here, and the recent history of monthly readings is here. Unadjusted GHCN is normally used, but if you click the TempLS button there, it will show data with adjusted, and also with different integration methods. There is an interactive graph using 1981-2010 base period here which you can use to show different periods, or compare with other indices. There is a general guide to TempLS here.

The reporting cycle starts with a report of the daily reanalysis index on about the 4th of the month. The next post is this, the TempLS report, usually about the 8th. Then when the GISS result comes out, usually about the 15th, I discuss it and compare with TempLS. The TempLS graph uses a spherical harmonics to the TempLS mesh residuals; the residuals are displayed more directly using a triangular grid in a better resolved WebGL plot here.

A list of earlier monthly reports of each series in date order is here:
  1. NCEP/NCAR Reanalysis report
  2. TempLS report
  3. GISS report and comparison with TempLS


  1. Hi Nick,
    Is your westnet email still active? I sent you a question.

  2. This RogTallbloke -- did you see he's trying to do some experimenting on his blog?

    What a blithering idiot ! I don't think the guy has ever stepped in a research lab LOL !