Detection and estimation of reflectivity gradients in the radar resolution volume using multiparameter radar measurements

Multiparameter radar measurements of rainfall, namely, reflectivity factor ZH , differential reflectivity ZDR , and specific differential phase KDP lie in a constrained threedimensional (3-D) space and therefore measurement of ZH , ZDR , or KDP should be consistent with the other two. This selfconsistency relationship between ZH , ZDR , and KDP is valid when the radar resolution volume is homogeneous. When there are reflectivity gradients within the radar resolution cell, the self-consistency relation is perturbed. This perturbation can be utilized to detect the presence of gradients in the radar resolution volume. This paper presents a technique to detect and estimate reflectivity gradients in the resolution cell. The technique is evaluated using theoretical analysis as well as experimental data collected by the NCAR CP-2 radar. It is demonstrated that the presence of reflectivity gradients larger than a few decibels can be detected using the algorithm developed in this paper.