On 02/03/2020 12:11, Julian Mayes wrote:
I thought I would pose this question here as there is a concentration of retired and (maybe?) current Met Office staff here with experience of observation networks.

In the current issue of Weather - in Weather Log - we find that 14 of the 21 UK sites listed give figures for days with snow lying and fog. Meanwhile, a further 4 just have a fog figure. 3 sites have no such data at all. My question is - does the existence of data imply that a station is staffed or part or maybe all of a day or is it simply a reflection of the appropriate sensor being installed? Are the observations comparable - for example, the snow depth sensor cannot find a representative patch of ground in the enclosure as the human can.

On a separate issue, no sunshine data is now available for Valley, Durham and Cambridge, each sites with long term records of sunshine on the old Campbell-Stokes instrument. (off hand I can't remember if it is Cambridge NIAB or the Botanic Gardens shown). It is even worse for the Europe list, including many capital cities which really must have sunshine data.

Many thanks, Julian
Molesey, Surrey.

If you have access to the synops, these have codes which say weather
each station's observation was manned or automatic, whether there was
weather reported or not and info about precipitation.
AFAIK there are no synops now, it's all BUFR code. Ogimet (and others)
convert BUFR to SYNOP, but how accurate it is I don't know. It can get a
bit complicated if stations are only manned (personed?) for some of the
time - like Benson, my local Met station.
On the question of fog at coastal stations, I'm pretty sure that the
worst visibility is reported, but only inland. If fog is drifting onto
land just over the way, then the visibility can go up and down like a
yoyo. Perhaps that's what happened at Camborne - the fog was within
1000m but wasn't at the station - adjacent fog should have been reported.
The other issue, data at 0900, isn't that a throwback to when there were
no AWSs and many sites only reported climatologically. I suspect that
they are kept for consistency.
Are the climat reports online? I suspect that they have similar groups
to the SYNOPs. But trying to find decodes for these is a bit of a
nightmare. I have a decode for the SYNOP code, but it's quite old now.
And I left the Met Office eight years ago (this month), so I might be
completely out of date.
Where's Bruce when you need him!