The Improvement to the Specific Differential Phase Estimation with the Modified Linear Programming Method

This study presents an approach to improve the estimation of specific differential phase (K_DP) by combing the linear programming method (LP) and the self-consistent constraint method. The self-consistent constraint among horizontal reflectivity factor (Z_h), differential reflectivity (Z_DR), and K_DP in rain is derived from the raindrop size distribution observations collected by a 2D video disdrometer (2DVD) in East China. Results with simulated data show the proposed algorithm has a good performance. As the traditional LP method uses a unified nonnegative lower boundary of K_DP, it can't resolve the K_DP accurately in the heavy rainfall region where the measured copolar differential phase (Y_DP) provides less effective information of precipitation property. The modified LP method, however, can overcome this problem by using self-consistent constraints. Furthermore, the application of the modified LP method in two heavy rainfall cases observed by a C-band Polarimetric Radar demonstrates its superiority to the traditional LP method in K_DP estimations.