Specific Differential Phase Estimation in the Presence of Nonuniform Rainfall Medium along the Path

Abstract

Specific differential propagation phase (KDP) is estimated as the slope of the differential propagation phase (ΦDP). The estimate of specific differential propagation phase is typically obtained over a path to minimize measurement error. It is shown that the estimate of specific differential phase over a nonuniform rainfall path is biased, and the bias increases with increased reflectivity variation along the path. It is also shown that the bias can be both positive and negative depending on the nature of nonuniformity in the propagation path. Three models for nonuniform reflectivity variation along the precipitation path are studied. A simple algorithm is presented to correct the bias in the estimation of KDP due to nonuniform rainfall paths. Multiparameter radar data collected over central Florida are analyzed and compared to the theoretical results developed in this paper.