A Theoretical Study of Estimations of Rain and Hail Rates in Mixed-Phase Areas with Dual Linear Polarization Radar
Liu Liping(Chinese Academy of Meteorological Science, Beijing 100081)
By using the model of hail shape, orientation and size distributions of rain and hail, the values of reflectivity (ZH ), differential reflectivity (ZDR ) and differential propagation phase shift (KDP) in rain and hail areas, and contributions of rain and hails to those parameters are examined. The results show that the reflectivity of hail measured by C band polarization radar decreases with hail rate when hail rate is large, the KDP in hail is related with the shape, orientation and size of hail. In the mixture of rain and hail, the main contribution of ZH is from hail, and rain is primary factor to affect KDP, and both rain and hail have contribution to ZDR , and ZH and KDP in rain have good correlation. Then we introduce a simple method to estimate hail and rain rates in mixed phase area with ZH, ZDR and KDP , analyze the measured errors with size distribution, radar measurement errors and effects of hail on KDP .