Saturday, June 15, 2024

GISS May global temperature down by 0.19°C from April.

The GISS V4 land/ocean temperature anomaly was 1.14°C in May, down from 1.33°C in April. This fall is similar to the 0.168°C reported here for TempLS.

As with TempLS, May was the warmest May in the record - next was 1.01°C in 2020.

I mentioned in the earlier post that the TempLS was made on a reduced number of stations that had reported.    Even now only 3303 non-US stations have reported, whereas last year there would have been over 4000. So it seems to be a permament change.

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

Wednesday, June 12, 2024

GHCN V4 changes.

AS I mentioned in my previous post, GHCN results have been coming through more slowly. I have been following a rule for posting, that I wait for 3800 non-US land stations to report. In April I was a little short, but in May, only 3320 stations by the 11th. So I investigated to see what is going on.
It seems that just a few countries are reporting a lot fewer stations than before; specifically, Canada, Australia and Scandinavian countries. It could be said that their previous roster of stations was excessive, but this is a drastic change. Here is a table of the recent numbers of leading countries:
Non-US Total488844974588439439123319

The US is low but that may be temporary, and anyway, it has far more than needed. But Canada is way down, and Australia has been down all this year. Sweden, Finland and Norway have been down for two months, but the coverage before was excessive. So I'm not worried about the change - I just note it.
To see what this looks like in detail, here is my home state of Victoria in April 2023, and then in April 2024:

Before the change, there were 9 stations in the Melbourne metro area, now just two, which seems reasonable. But it leaves most of the Victoria interior without data.
Anyway, for now I'll use data from 3200 non-US stations as the trigger for posting.

Tuesday, June 11, 2024

May global surface TempLS down 0.168°C from April, but still warmest May in record.

The TempLS FEM anomaly (1961-90 base) was 1.013°C in May, down from 1.181°C in April. It was still the warmest May in the record, ahead of 0.859°C in 2020. The NCEP/NCAR reanalysis base index fell by 0.044°C.

I'm late posting this month. GHCN data has been slow coming in. I have rules for posting, the most critical is that there be 3800 land stations outside US. But this month there are only 3320 so far. It seems to be a long term change, so there is not much point in waiting longer. The deficit is in just a few countries which were previously very well covered, so it may be by design. Anyway, I'll write a post later today analysing that.

Here is the corresponding stacked graph, showing how much hotter recent months have been:

Here is the temperature map, using the FEM-based map of anomalies. Use the arrows to see different 2D projections.

As always, the 3D globe map gives better detail. There are more graphs and a station map in the ongoing report which is updated daily.