Combining Radar Attenuation and Partial Beam Blockage Corrections for Improved Quantitative Application

摘要

Partial beam blockage (PBB) correction is an indispensable step in weather radar data quality control and subsequent quantitative applications, such as precipitation estimation, especially in urban and/or complex terrain environments. This paper developed a novel PBB correction procedure based on the improved ZPHI method for attenuation correction and regional specific differential propagation phase (K-DP)-reflectivity (Z(H)) relationship derived from in situ raindrop size distribution (DSD) measurements. The practical performance of this PBB correction technique was evaluated through comparing the spatial continuity of reflectivity measurements, the consistency between radar-measured and DSD-derived K-DP and Z(H) relationships, as well as rainfall estimates based on R(Z(H)) and R(K-DP). The results showed that through incorporating attenuation and PBB corrections (i) the spatial continuity of Z(H) measurements can effectively be enhanced; (ii) the distribution of radar-measured K-DP versus Z(H) is more consistent with the DSD-derived K-DP versus Z(H); (iii) the measured Z(H) from a C-band radar in the PBB-affected area becomes more consistent with collocated S-band measurements, particularly in the rainstorm center area where Z(H) is larger than 30 dBZ; and (iv) rainfall estimates based on R(Z(H)) in the PBB-affected area are incrementally improved with better spatial continuity and the performance tends to be more comparable with R(K-DP).