Friday, May 17, 2019

GISS April global down 0.12°C from March.

The GISS land/ocean temperature anomaly fell 0.12°C in April. The anomaly average was 0.99°C, down from March 1.11°C. It compared with a 0.097°C fall in TempLS V4 mesh. As with TempLS, because March was so warm, dhe drop still meant that last month was the second warmest April in the record.

The overall pattern was similar to that in TempLS. Warm in all of Eastern Asia, especially Siberia. Warm in Europe, NW Canada and Alaska, and much of Africa. Mostly cool in Antarctica.

As usual here, I will compare the GISS and previous TempLS plots below the jump. I am planning to post in the next few days about a better style of TempLS plotting

Here is GISS V4

And here is the TempLS V4 spherical harmonics plot

This post is part of a series that has now run for six years. The GISS data completes the month cycle, and is compared with the TempLS result and map. GISS lists its reports here, and I post the monthly averages here.
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. I think you meant "down 0.099C."

    1. Well, GISS only goes to two decimals. I make 1.11-0.99=0.12.

  2. I update my prediction for GISS temperature anomaly using data up to Apr19.
    MAM19 0.97+-0.04
    JJA19 0.87+-0.13
    SON19 1.01+-0.15
    J-D19 0.95+-0.08
    DJF20 0.99+-0.25
    MAM19 1.01+-0.04
    JJA19 0.90+-0.12
    SON19 1.03+-0.15
    J-D19 0.99+-0.08
    DJF20 1.04+-0.24

  3. Looks like HadCRUT4 for March is running way late, about 3 weeks late so far, and I see nothing on their website to indicate why. Does anyone know what has caused the delay?

    1. Same thing with BEST. No March (or April) values so far. I asked them by email, but I got no response.

    2. Although neither of them explicitly use GHCN V4, the delay matches the timing of its introduction.

    3. Pretty sure it's due to SST data, not the land data. BEST have released an April land-only average and they use HadSST3 for ocean data. Looks like March HadSST3 was only published on Friday just gone so presumably BEST will update to March in the next few days.

      HadSST3 used to update on a similar timescale to ERSST - first or second week of the following month - but now seem to be a couple of months behind.