Influence of the Raindrop Axis Ratio on Radar Parameters and Their Relationships

Based on the observational data of raindrop size distributions (DSDs) from Parsivel optical disdrometers in Qixian and Jiexiu of Shanxi Province during the period of July and August 2008, a contrast about the characteristics of DSDs and the statistical probability of radar parameters are provided. And then, the dependences of rainfall R and rainwater content W related with reflectivity Z upon axis ratio are discussed. It shows that as the rainfall (R) increases, the corrected R is improved, especially when R>5 mm·h-1. As reflectivity Z is proportional to the 6th power of diameter (D), the corrected reflectivity (Zcorr) is changed much more quickly. At last, on the basis of axis ratio, the Znoncorr-Rcorr relationship and the reflectivity Z and rainwater content W relationship (Z-W) offer a scientific ground for radar measurement of precipitation and a deep-going way research on cloud micro-physical processes and the effects of thunder-lightning on regional precipitation is determined.