Practical Aspects of Radar Rainfall Estimation Using Specific Differential Propagation Phase

Abstract

Rainfall estimation using specific differential phase (KDP) involves estimation of KDP over a propagation path. The choice of pathlength plays an important role in the performance of rainfall algorithms using KDP. The path-integrated nature of KDP-based rainfall estimates may involve inhomogeneous paths, thereby having potential implications on the pathlengths used in algorithms for rainfall estimation and measurement errors. The effect of inhomogeneous rainfall paths (over which KDP is estimated) on the choice of rainfall rate algorithms is studied as a function of rain pathlength. Rainfall estimation is biased when algorithms relating rainfall rate and KDP are used over nonuniform paths. This bias is evaluated and compared for different rainfall algorithms. Radar and rain gauge data collected during the Convection and Precipitation/Electrification Experiment (CaPE) are used to evaluate the performance of KDP-based rainfall algorithms, for different pathlengths.