On Jan 17, 10:39*am, John Hall wrote:
In article
,
*Stephen Burt writes:





On 16 Jan, 21:47, "Colin Youngs" wrote:
"Stephen Burt" schreef in bericht
news:0a0ec3ba-e956-47ed-b2ff-

Drumalbin, Bingley, Trawsgoed, Aberdaron and Charlwood 13 mm, Little
Rissington 16 mm, Sennybridge 21 mm, Capel Curig and Lake Vyrnwy 24 mm,
Spadeadam 25 mm, Aviemore 48 mm.

Hmmm ... I wonder how many of these large totals we've seen last few
days are from melting snow in unmanned and unchecked tipping bucket
gauges ...
______________

I noticed this on Tuesday when 3 places in the north of Scotland reported
high rainfall totals without anything on the radar to back them up -
Tulloch Bridge 26 mm, Aboyne 28 mm, Altnaharra 44 mm.

I also had it in mind on the following days - but from this distance and
without specialist knowledge, I was not sure whether it was still a factor.
I should have been sceptical about the Aviemore figure since it was so much
greater than the others.

I also noticed during the periods of snowfall that the rainfall totals often
seemed too low for the depths of snow being reported.

Colin Youngs
Brussels

No criticism of your excellent reporting intended, Colin. I find it a
shame that these anomalies will probably get left in the
climatological record through lack of action or interest. So much for
maintaining an _accurate_ record of the nation's weather! Symons, Mill
et al must be positively spiining in their graves at this vandalism of
the country's rainfall records.

Philip Eden made essentially the same point in his weekly piece in
yesterday's Telegraph. It would be even worse if heavy snowfall occurred
in one month and the thaw the following month, as then the monthly
totals would be wrong as well as the daily ones.
--
John Hall
* * * * * *"Acting is merely the art of keeping a large group of people
* * * * * * from coughing."
* * * * * * * * * * * * * * * Sir Ralph Richardson (1902-83)- Hide quoted text -

- Show quoted text -

Having read this thread I got in touch with the observing contact
point, and it seems our fears are unfounded.
Hope I get this right!
Rainfall records are based primarily on the 0900 to 0900 rainfall day.
All the 100s of climate observers read their rainfall at 0900, and
melt any snowfall to give a rain equivalent.
Manned Met stations read an ordinary manual gauge at 0900 each day
too, to check that their automatic
kit is accurate.
If the auto gauge is blocked with snow, the 24 hour reading is
replaced by the rain equivalent from the manual gauge.
No similar efforts are made for other rainfall periods as reported at
0600, 1800 etc. Unfortunately these are the periods used by sites
such as the ones Colin gets his info from, which often makes it
incorrect.
The important thing is that the rainfall day data is correct.
At unattended automatic stations very little can be done until the
snow melts. The accumulated readings of snowmelt are then re-
allocated to the correct rainfall days by comparing with the nearest
climate stations or manned Met sites.
So, although it may not be the case until some weeks after the event,
the readings are eventually accurate.

Jim