ESTIMATION OF RAINFALL RATE IN EASTERN TIBET USING GROUND-BASED RADAR OBSERVATIONS: METHOD DEVELOPMENT

Abstract

This paper proposes a method for estimating rainfall rate from ground-based radar observations in eastern Tibet. Firstly, the radar reflectivity-rain rate (Z-R) relationship is derived by regression analysis using the hourly data of a single rain gauge located near the radar and the corresponding radar reflectivity over a period of more than two months. Two different relationships are obtained for stratiformand convective rain types. Secondly, an automated convective-stratiform rain classification methodis introduced that uses the horizontal radar echo structure to identify convective regions and classifies the remainder as stratiform areas. The classification algorithm is verified against visual inspections of horizontal and vertical radar echo structures. Finally, the rain rate is estimated from the radar reflectivity for the rain gauge site using the derived Z-R relationships and the rain type information produced by the classification algorithm. The comparison of the estimation and the gauge data suggests good accuracy.