Rainfall sensor NR4M

Description

Precipitation measurement: Criteria for the location of the precipitation sensor

The accuracy of the precipitation measurement depends on a clean measuring device and the correct installation site. Depending on the wind speed, a certain proportion of the precipitation particles is driven over the collecting surface. Therefore, an installation in completely free terrain as well as in the immediate vicinity of an obstacle should be avoided. For the installation e.g. gardens are suitable, in which hedges or the like offer wind protection. Since the precipitation measurement is a point measurement, the installation site should be selected so that the measured values are representative for as large an area as possible.
According to WMO recommendations, precipitation gauges should be placed at a distance of at least two to four times the height of the nearest obstacle. However, at least a height angle should be less than 45″ with respect to the surrounding plants. The distance between the upper edge of the rain gauge and the ground should be 1 m.
If snow is regularly expected in the installation area, this distance should be increased. The rain gauge is to be set up vibration-free. To ensure correct measurements, the precipitation gauge must be set up in a suitable location that is typical for the local climate, is little affected by the wind and also reliably collects precipitation falling at an angle.
The German Weather Service stipulates a height of the collecting surface of 1 rn at a station altitude of <500 m above sea level, 1.5 m at a station altitude of >500 m above sea level and 2 m above ground at a station altitude of >800 m above sea level.