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Rain Gauges for measuring rainfall

Two types of rain gauge are used. The photographs in the top row show the Snowdon type gauge. This consists of an 18" long copper tube with a diameter of 5". It is set in the ground such that 12" of the gauge are above the grass surface. Looking at the photograph on the right we can see the various components of the gauge. Starting on the left is the removable funnel, then a copper bucket for any overflow water from the collecting bottle. Continuing from L to R we have the glass rain measurer then the glass collecting bottle. Finally there is the base of the gauge into which the various components fit.

The Davis AWS Rain Collector (Right) The Davis Rain Collector is an example of a tilting bucket rain gauge. Beneath the collecting funnel is a see-saw mechanism of two small buckets which tilts once with every 0.2mm rainfall. The tilt is recorded by a sensor which transmits the information by cable to the display monitor and the PC. Experience has shown that this unit tends to under read by about 10%. I therefore use the rain collector information for the timing of rainfall events and the Snowdon gauge for actual amounts