Tuesday, September 17, 2019

GISS August global down 0.04°C from July.

The GISS V4 land/ocean temperature anomaly fell 0.04°C in August. The anomaly average was 0.90°C, down from July 0.94°C. It compared with a 0.029°C fall in TempLS V4 mesh

The overall pattern was similar to that in TempLS. Warm in Africa, N central Siberia, NE Canada, NE Pacific. Cool in a band from US Great Lakes to NW Canada and in NW Russia. Mostly warm in Antarctica.

As usual here, I will compare the GISS and earlier TempLS plots below the jump.

Here is GISS V4

And here is the TempLS V4 LOESS-based plot

This post is part of a series that has now run for seven 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. Annual average for 2019, eight months in, is now anomaly 0.966C.

    Second behind 1.02C for 2016 and ahead of 0.93C for 2018 in third place.

  2. I find August V4/HadSST3 is just 0.01C warmer than July, which is essentially unchanged. August is 0.82C relative to 1961-1990.

    However it seems that GHCN have stopped updating V3, which I find to be premature. Do you know why ?


    1. Clive,
      I don't know why they have discontinued V3, but I suppose there may be some effort required for the homogenisation. For the unadjusted data, they were really just transcribing the Climat data, which is fortunately still being posted. But it's harder to download.

  3. I update my prediction for GISS temperature anomaly using data up to Aug19.
    SON19 1.02+-0.12
    J-D19 0.99+-0.04
    DJF20 1.07+-0.21
    MAM20 1.08+-0.18
    JJA20 0.94+-0.15
    The year 2019 of the GISS LOTI will be most likely (formal prob. greater then 96%) the second warmest, only behind 2016.

    Assuming the 2019 temperature anomaly the prediction for 2020 is:
    J-D20 1.02+-0.14

    This would be a fifty-fifty chance of a new record in 2020.
    Note that the results may be less accurate due to still using old MEI values.
    I've tried new MEI2 but with no good results due to no data before 1979.

    1. Here is more evidence that ENSO is not close to being chaotic or random. If a forcing signal is convolved with an annual impulse, the Fourier spectrum will be symmetric about the 0.5/year frequency.

      Easy enough to check:


      There are so many interesting spectral features in these climate indices that are worth looking at.