Sampling of precipitation water

Horizontal precipitations (dew, frozen mist, ice accretion, condensed fog) are usually not analysed. The quantity of vertical precipitation is measured in practice by a dense network of hydrometrological stations using the standard method of the World Meteorological Organization. 

Rainfall water and falling snow samples are collected into a sample container through a funnel, or into a deep and wide dish. An average sample is taken from ice, it is placed in a wide-neck sample container and allowed to melt at room temperature. 

Automatic systems for precipitation sampling are usually designed so that it is possible to take dust-free samples. The automatic mechanism of commercially produced systems is focused on opening of the sample containers during rain and closing in the periods without rain. The lid of the system is controlled by a switch sensitive to the very first rain drops or snow flakes. Usually, the conductivity of rain water is utilized which connects two insulated points with opposite electric charges on an inclined and slightly heated plate. 

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