Saturday, February 16, 2019

GISS January global down 0.01°C from December, 0.11°C higher than November.

Update With this post I initially misread the GISS data file, taking values from the end of the row which are period averages, rather than the correct monthly averages for November and December, as ErikGBL noted in comments. It actually made only a small difference, but I have fixed it. I first had a small rise from December, now a small drop.
The GISS land/ocean temperature anomaly fell 0.01°C in January, which followed a 0.11°C rise the month before. The January anomaly average was 0.88°C, down from December 0.89°C. It compared with a 0.034°C fall in TempLS mesh . Jim Hansen's report is here.

The overall pattern was similar to that in TempLS. The US was actually fairly warm overall, despite the cold snap at the end of the month. Canada's Arctic islands were very cold, but a big band of warmth in NW Canada/Alaska, and another from E Siberia (which also had a cold snap) through to the Caspian region. SE Australia was hot.

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

Here is GISS

And here is the TempLS 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. Gistemp v4 with GHCN4 is finally here

    I don't know why they call it beta, because GHCN 4 hasn't been beta for a while.
    Anyway, with v4 the temperatures and trends of the recent few decades have gone up, probably because the arctic cooling bias has been removed ( more arctic stations convince the PHA that the rapid arctic warming is real).

    In v4 the Jan 2019 temperature is 0.95 C, up 0.05 from Dec.
    The 1979-2018 trend in v4 is 0.183 C/decade, compared to 0.171 in v3.

  2. Think the map you're showing is from the new GHCNv4 edition.

    Interesting to compare the GHCNv3 and v4 GISS maps using 250km smoothing, it's a fairly substantial improvement in coverage.

  3. The title should be "GISS January down 0.01°C from December, 0.10°C higher than November."

    and the first sentence:

    "The GISS land/ocean temperature was down 0.01°C in January, which followed a 0.11°C rise the month before. The January anomaly average was 0.88°C, down from December 0.89°C"

    I think you (or your code) have been confused by by the numbers at the end of the 2018 data row which are the two last average quarter temperatures of 2018, not November and December. (Your graph and table on your "Latest ice and temperature" data page have actually got it right)

    1. Erik
      Thanks. Yes, I did notice discrepancies between this and past versions, and did not immediately realise the effect of change to V4. I thought they were shutdown isues. I'll fix.