Application of X-band Polarimetric Phased-array Radars in Quantitative Precipitation Estimation

The performance of different quantitative precipitation estimation (QPE) relationships is examined using thepolarimetric variables from the X-band polarimetric phased-array radars in Guangzhou, China. Three QPE approaches,namely, R(ZH), R(ZH, ZDR) and R(KDP), are developed for horizontal reflectivity, differential reflectivity and specific phaseshift rate, respectively. The estimation parameters are determined by fitting the relationships to the observed radarvariables using the T-matrix method. The QPE relationships were examined using the data of four heavy precipitationevents in southern China. The examination shows that the R(ZH) approach performs better for the precipitation rate lessthan 5 mm h-1, and R(KDP) is better for the rate higher than 5 mm h-2, while R(ZH, ZDR) has the worst performance. Anadaptive approach is developed by taking the advantages of both R(ZH) and R(KDP) approaches to improve the QPEaccuracy.