Tuesday, June 18, 2019

GISS May global down 0.11°C from April.

The GISS land/ocean temperature anomaly fell 0.12°C in May. The anomaly average was 0.86°C, down from April 0.97°C. It compared with a 0.149°C fall in TempLS V4 mesh. I should note that there were late moves in both indices. GISS' April figure dropped 0.02°C between posting last month and now, making a total drop of 0.13. I note that GISS says that this month is the first using GHCN V4 (other than beta); the change may be part of that. The drop in TempLS is somewhat less than originally posted. I posted that rather early, since all major countries seemed to have coverage, and I got stable results two days in a row. The latter proved illusory, though. A minor nuisance with GHCN V4 is that they keep adding to the inventory. I have resolved to only update it once a month, and this was the first time it had been updated automatically. It didn't quite work; the net result was that my apparent stability was due to data not being updated. It should be OK in future.

The overall pattern was similar to that in TempLS. Warm in most of Asia and Africa. Cool in central Europe and much of the N America (but warm in NW). Arctic warm.

As usual here, I will compare the GISS and previous TempLS plots below the jump. I have now switched from my spherical harmonics based TempLS plots to LOESS based, which gives a more similar resolution.

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 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 comment:

  1. I update my prediction for GISS temperature anomaly using data up to May19.
    JJA19 0.87+-0.13
    SON19 1.00+-0.15
    J-D19 0.94+-0.08
    DJF20 0.99+-0.26
    MAM20 1.04+-0.20
    JJA19 0.90+-0.12
    SON19 1.01+-0.15
    J-D19 0.97+-0.07
    DJF20 1.03+-0.25
    MAM20 1.05+-0.20