Rainfall Measurements with the Polarimetric WSR-88D Radar.

摘要

Improvement of Quantitative Precipitation Estimation (QPE) is one of the primary benefits of a dual-polarization radar. In addition to conventional radar reflectivity factor Z, a polarimetric radar is capable to measure differential reflectivity ZDR, specific differential phase KDP, and the cross-correlation coefficient nhv between two orthogonally polarized radar returns. Using multiparameter radar information instead of radar reflectivity alone helps to significantly improve the radar data quality, distinguish rain echoes from the radar signals caused by other scatterers (snow, ground clutter, insects, birds, chaff, etc.), and to reduce an impact of drop size distribution (DSD) variability on the quality of rainfall estimation. Differential reflectivity ZDR is a good measure of the median drop diameter that should be taken into account for more accurate rain measurements. Among the indisputable advantages of polarimetric rainfall estimation based on specific differential phase KDP is its immunity to radar miscalibration, attenuation in precipitation, and partial blockage of radar beam.