Comparison and Verification of Rainfall Validation with Parsivel2 and X-band Dual-Polarization Radar

Abstract

Observations acquired from Parsivel2 disdrometer located at the haidian station and X-band dual-polarization radar of IAP (Institute of Atmospheric Physics) were compared and analyzed for the process of severe weather in Beijing on July 20, 2016. The radar reflectivity factor from disdrometer and radar are matched and compared using multiple averaging schemes with different grid sizes in neighboring regions considering the consistency of time and space as well. The accuracy of QPE (quantitative precipitation estimation) will be affected by the attenuation of X-band radar, and can be evaluated precisely from disdrometer observation. In this study, disdrometer was used to obtain the precipitation intensity and reflectivity factor. Based on raindrop size distribution observation and the least square method, a Z/R relation was simulated and applied to QPE calculation, QPE from Z/R relationship of convention and correction, polarization parameters derived, disdrometer observed and from automatic rain gauges were compared and validated. The results show that the corrected QPE were much closer to the Parsivel2 observation, and the QPE from polarization parameter was the optimal one.