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:

	May23	Jan	Feb	Mar	Apr	May
USA	6365	6308	6333	6251	6220	4867
Non-US Total	4888	4497	4588	4394	3912	3319
CAN	872	774	883	872	724	164
RUS	500	532	545	543	510	504
SWE	206	204	205	184	10	10
CHINA	200	201	199	87	200	201
GER	167	168	168	169	160	160
FIN	168	165	169	169	29	29
JAP	59	150	150	150	150	150
AUS	540	133	133	139	137	136
NOR	109	111	110	110	21	22
SPAIN	98	100	100	97	84	84
INDO	93	92	92	98	92	99

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.