The rain gauge

The amount of water that falls on the ground is expressed in millimetres, i.e. the height the water would have reached had it fallen on a horizontal impermeable surface. One millimetre of rain that falls on a surface of 1 m2 is equivalent to one litre of water collected.
The amount of rain that falls is measured with pluviographs. These consist of a cylinder shaped container, positioned in a special weather cabin, above which is a collection funnel that has standard characteristics. The water that is collected is weighed and the data are recorded automatically and forwarded to a processing unit. Snowfall is collected on special tables, and the height is measured with measuring rods. Electric heating elements positioned on the funnel of the rain gauge melt the snow and thus the millimetres of rain, equivalent to the snowfall are obtained.

 
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