基于星载SAR观测的改进型NRCS模型研究  

Research on an improved NRCS model based on spaceborne SAR observation

作　　者：徐振斌 谢亚楠[1] 王瑞[1] XU Zhenbin;XIE Ya′nan;WANG Rui(Department of Communication and Information Engineering,Shanghai University,Shanghai 200444,China)

机构地区：[1]上海大学通信与信息工程学院,上海200444

出　　处：《气象与环境学报》2024年第5期106-111,共6页Journal of Meteorology and Environment

基　　金：国家自然科学基金项目(62071286);“提高合成孔径雷达数据反演降水分布精度的关键问题研究”(20Z00430)共同资助。

摘　　要：通过不同相态降雨粒子散射衰减特性的回波路径分析,推导了归一化雷达散射截面(Normalized Radar Cross Section, NRCS)计算公式。利用1998年低纬度热带陆地和海洋实测对流降雨垂直廓线,根据合成孔径雷达(Synthetic Aperture Radar, SAR)的基于定向模型统计(Model-Oriented Statistical, MOS)地面降水量反演算法验证NRCS优化效果。结果表明:优化后的NRCS模型能提高6.17%的回波衰减;回波衰减量的提高表明,在MOS算法低估的地面降雨量范围内,优化后的NRCS模型能提高MOS算法的地面降雨量反演精度,反演的平均误差降低了1.56%。但在MOS算法高估的地面降雨量范围内,优化后的NRCS模型反而会增大MOS算法的反演误差。因此,改进型的NRCS模型仅适用于MOS算法低估地面降雨量的情况。The Normalized Radar Cross Section(NRCS)calculation formula is derived by analyzing the echo paths of the scattering attenuation characteristics of rainfall particles in different phases.Using the vertical profiles of convective rainfall measured over low-latitude tropical land and ocean in 1998,the optimization of NRCS is validated based on the Model-Oriented Statistical(MOS)surface rainfall retrieval algorithm of Synthetic Aperture Radar(SAR).The results show that the optimized NRCS model can improve the echo attenuation by about 6.17%.The improvement of echo attenuation indicates that the optimized NRCS model can improve the surface rainfall retrieval accuracy of MOS algorithm in the range of surface rainfall underestimated by MOS algorithm,and the average retrieval error is reduced by about 1.56%.However,in the range of surface rainfall overestimated by MOS algorithm,the optimized NRCS model will increase the retrieval error of MOS algorithm.Therefore,the improved NRCS model is only applicable to the case where the MOS algorithm underestimates the surface rainfall.

关 键 词：星载合成孔径雷达 反演算法 归一化雷达散射截面 降雨垂直廓线 

分 类 号：P412.25[天文地球—大气科学及气象学]