"Zak" wrote in message
...
In message , Phil Layton
writes
Thanks very much Stephen (and Will for pi!). I will have a go at this, as I
reckon I have a 20% underread compared to a manual guage here.

Phil
Repeated thanks to all, particularly Stephen Burt and John Dann.

In tests, it took about 40 mins for 500ml to run through my improvised
feed and the result?

Well, calculations said that 500ml should translate into 23.64mm and the
average of two runs was 23.1mm - close enough for my peace of mind.

That still leaves me wondering at the 20% anomaly - the other gauge (1m
away and 0.6m lower) checked out as accurate too. Can that separation
cause such a large disparity?


Hi Zak. In a word - yes!!!

If you look back through British Rainfall at the beginning of the 20th Century
when folk were trying to decide on best gauge design and site, it was quickly
concluded that elevated gauges would under-read due to air currents deflecting
rain and greater exposure to wind generally.

I have exactly the same problem as you my Davis reads 20% lower than my rain
gauge 2m away and just over 1m lower.

Cheers,

Will
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