"Steve Jackson" wrote in message
...
An interesting thread, especially in view of the difficulties of measuring
snowfall in rain gauges.

We have a heater in one of our MO office gauges, so that when it snows the
snow melts on impact and enters the gauge in the same way as rain; in the
other identical MO gauge, there is no heater, and that did underead in the
smow last month, by 9% overall.

Steve Jackson
Bablake Weather Station
Coventry UK
www.bablakeweather.co.uk

I have a Young 52202 gauge with heater, for "all year round use" according
to the manufacturer. The heater was supplied as 'automatic', but I quickly
discovered that it came on when the air temperature dropped below 10C. I
queried this with Youngs, saying I had expected it to switch on around 0 or
+1C, but they insisted that it was designed to operate as mine was doing. So
i fitted a manual over-ride switch, and I only switch it on when I expect
snow. The reason is that a heated funnel causes huge losses due to
evaporation. In the recent snowy episode, the heated gauge recorded less
than half that of snow melted into the 5 inch standard gauge. This has also
been my experience in previous snow events. Anyone considering using a
heated gauge should consider carefully the problem with evaporation, and
no-one should rely on a heated gauge in the absence of standard check gauge
on the same site. If the Met Office are using heated gauges, they should, I
hope, make due allowance for these losses.



--
Bernard Burton

Wokingham Berkshire.

Weather data and satellite images at:
http://www.woksat.info/wwp.html