This paper focuses on the systematic errors of a precipitation measurement by gauges. Usually, the measured rainfall is underestimated.
Underestimation varies from 10 % in a case of rain after 50 % or more in a case of snowfall. I chose two stations in the Czech Republic, a Hradec Kralové station is situated in lowlands and a Svratouch station is situated in highlands.
Chosen period was 1961-1990. The initial results show that after corrections the Hradec has an increase of 19 % and the Svratouch 32 % (in compare with measured precipitation).
However, it needs further refinement.