Classification system of precipitation gauge site exposure: Evaluation and application

The precipitation gauge site exposure is assessed from the station history records. Four classes and three interim classes ranging from open to protected gauge sites are used. They are characterized by the average vertical angle of obstacles around the gauge, as measured in eight directions of the wind rose. The accuracy of class estimates was checked in the field, and the error for an experienced person was found to be approximately ±0.5 of a class. Applications of the classification system for estimation of wind-induced error of precipitation measurement and for detection of inhomogeneities of precipitation time-series are discussed.