Adjustment of tipping-bucket precipitation gauge measurements

Abstract The 6-year mean annual difference in precipitation values as measured using the Hellmann gauge and the tipping-bucket recording precipitation gauge at the same open site at the Airport of Geneva amounts to 14%. The tipping-bucket gauge shows less precipitation. The percentage differences in daily precipitation amounts depend on wind speed and intensity of precipitation. The nonlinear prediction model which is based on 576 daily values of the period 1980–1985 shows that there is a threshold value of precipitation intensity for each interval of wind speed. This threshold value increases with increasing wind speed. Below the threshold value a sharp increase in percentage difference exists with decreasing intensity. Relationships of a similar nature have a general application for corrections of the wind-induced error of precipitation measurement or for adjustments of precipitation values from one gauge type to the other.