Wednesday, May 5, 2021

April global surface TempLS down 0.165°C from March.

The TempLS mesh anomaly (1961-90 base) was 0.608°C in April, down from 0.773°C in March. That takes away much of the rise in March, and goes back to about the level in Dec/Jan, though warmer than February. It was the coolest April since 2013. The NCEP/NCAR reanalysis base index did not rise as much in March, and so did not fall in April, rising just 0.016°C. Again, April was about the level of Dec/Jan.

Many Moyhu readers will have experienced the cold patches, which were in Eastern US (also Alaska and NW Canada), Europe and most of Australia. There was also a cold band through Afghanistan/China. N Africa, S America, NE Canada and NW Siberia (and much of Arctic) were warm; Antarctica was cold.

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


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