Combining GPM DPR with S-band Radar to Retrieve RSD

CHEN Xintao, LIU Xiaoyang†

Department of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing 100871; † Corresponding author, E-mail: xyl@pku.edu.cn

Abstract For solving the dual-value problem of RSD raindrop size distribution retrieval algorithm using GPMCO DPR data, a solution is put forward: combining the observation data of S-band weather radar and GPM-CO DPR to provide determinant for the dual-value problem. On the basis of completing the retrieval algorithm, the radar simulation program, Quickbeam, is utilized to validate the algorithm, and actual observation data is utilized to validate the algorithm as well. The results of theoretical validation show that the correlation coefficients between retrieved data and input data are over 0.99, and the results of validation with actual observation data show that the retrieved RSD can reflect the raindrop distribution situation of the rainfall process. The algorithm can help to solve the dual-value problem to o certain degree. Key words GPM project; DPR; S-band weather radar; RSD; retrieval algorithm; dual-value problem

全球降水观测(global precipitation measurement, GPM)计划是美国国家航空航天局(National Aeronautics and Space Administration, NASA)和日本宇宙航空研究开发机构(Japan Aerospace Exploration Agency, JAXA)主导的新一代卫星观测项目,为热带降雨观测任务(tropical rainfall measuring mission, TRMM)的升级版本, 其目标是实现对全球范围的降水观测。与TRMM相比, GPM计划的观测范围更广, 观测精度更高, 可以实现对弱降雨和降雪的观测。

作为GPM计划的核心组成部分, GPM核心观测

卫星(GPM Core Observatory, 简称GPM-CO)于2014年2月27日成功发射,3月开始返回观测数据。GPMCO上搭载的主要探测仪器为双频降水雷达(Dualfrequency Precipitation Radar, DPR)和GPM微波成像仪 (GPM Microwave Imager, GMI), 其中DPR为Trmm卫星上搭载的降水雷达(precipitation Radar, PR)的升级版, 有两个探测波段, 分别为与PR相似

[1]的13.6 GHZ的Ku波段和35.5 GHZ的Ka波段 。与Ku波段相比, Ka波段的波长更短, 可以探测降水强度更小的降雨和降雪过程, 但降水造成的衰减比Ku波段严重。