Thread: 700 mm/h ???
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Old August 5th 12, 10:50 PM posted to uk.sci.weather
Dartmoor Will Dartmoor Will is offline
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Default 700 mm/h ???


"johnd" wrote in message
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"Dartmoor Will" wrote in message
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Can 700 mm/h be correct, surely a malfunction due to the tipping bucket
mechanism being overwhelmed?


Well, certainly unlikely to be accurate at such extreme rain rates, but
all it means when you work it out (and for a 0.2mm TBR) is that two
successive tips were recorded about 1 second apart - close to the reality
check limit for a VP2 I suspect. (Though actually now I come to check it,
the spec says the max rain rate is 2438mm/hr - probably a conversion from
96"/hr ). I wonder if, transiently, the rain was falling into the
collector faster than it could pass through the central hole and hence
triggering two tips in very quick succession. In other words, perhaps at
seriously extreme rain rates the limiting factor becomes the rate at which
rain can exit through the orifice because I'm pretty sure that the buckets
can tip a bit more quickly than every second.

JGD


Thanks John that makes sense.
Certainly for a few minutes the rain was awesome. Large drops and many many
of them (like drizzle) which is an unusual density. The air was full of
water and I could not make out any cloud forms at all. I have never seen
such rain intensity, not even in thunderstorms. No doubt it occurs regularly
in the tropics and my son who has been to Sri Lanka said such rains were
fairly typical there.

What a day!
All drying up now.

http://www.lyneside.demon.co.uk/Hayt...antage_Pro.htm
Will Hand (Haytor, Devon, 1017 feet asl)
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