Chris Kidd wrote:
It's probably been discussed before, but...

The general idea is that rain gauges should be as flush with the ground as
possible to ensure that the catch is affected as little as possible by the
wind. Just to test this I put three idenitical TBR (Youngs) gauges at
rim-heights of 40cm, 100cm and 160cm above the ground. From 12/11/07 to
29/01/08 they collected 210.4, 213.2 and 216.5 mm respectively. Um...

Speaking as someone with a science background (and not necessarily in
climatology or whatever), I would be performing the same test with the
same gauges but changing the order of heights. Repeating this over
several observations (of, say one month) and trying all combinations
will minimise the effect of any difference in calibration that the
gauges have. You may also have localised effects, so trying the
experiment in many different locations and analysing the statistics over
all places will help to minimise that effect over time.

What you can't do is to do it once and take one set of results as
verbatim. The variability of precipitation could make accurate
statistical analysis difficult though.

--
Jonathan Stott
Canterbury Weather: http://www.canterburyweather.co.uk/
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