April global surface TempLS up 0.054°C from March.

The TempLS mesh anomaly (1961-90 base) was 1.010deg;C in April vs 0.947°C in March. This was similar to the rise in the NCEP/NCAR reanalysis base index, which was 0.045°C.

The prominent feature was a warm Arctic, extending into central Siberia, surrounded by a band of cool, in N America (except W USA) and from E Europe via N India to China. Warmish almost everywhere else, including W Europe.

I might comment here on my timing of posting. I maintain the latest numbers here, before and after posting. They become meaningful as soon as ERSST is posted, usually about the 4th. At that stage the large majority of the land data is also in (about 85%). But then the rate of new land data slows to a trickle, so there is a temptation to post at that point. In the previous two months, I did so, but the late data made a surprisingly large difference. This month, I held off for a while, but the result increased by only 0.01°C. I'll keep monitoring this.

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