星载降水测量雷达降水反演算法敏感性分析

Sensitivity analysis of precipitation rate retrieval algorithms for spaceborne precipitation radar

中文关键词:  GPM,FY-3G PMR,降水反演,相态,NUBF,敏感性分析

英文关键词:GPM,FY-3G PMR,Precipitation rate retrieval,Phase,NUBF,Sensitivity analysis

中文摘要:

      以GPM KuPR的实测资料作为代理数据，评估了FY-3G PMR原型算法的精度。在此基础上，对R-Dm初值、相态以及NUBF订正因子paramNUBF这三个参数进行了降水反演的敏感性分析。首先，对调了层云和对流的R-Dm初值，比较了初值调整前后滴谱廓线，雷达反射率因子廓线以及降水率廓线的变化；其次，设计敏感性试验，分析了相态的误判对降水反演精度的影响；最后，通过设置不同的paramNUBF，评估了paramNUBF对降水反演的敏感性。[结果和结论]结果表明，FY-3G PMR原型算法反演的降水结构及强弱分布和KuPR具有很好的一致性，反演的相对误差小于10%，相关系数优于0.95。敏感性分析的结果表明雷达反射率因子廓线以及降水率廓线的反演对R-D_m初值不敏感，但是滴谱廓线的反演对R-D_m初值却比较敏感。亮带层相态的误判尤其是混合相态和固态以及混合相态和液态之间的误判，会影响0℃层附近的空中降水，但对地面降水的影响不大。paramNUBF作为高敏感性因子，与真值的差异越大，降水率廓线反演的误差就越大。[目的]开展星载雷达降水反演算法的敏感性分析不仅可以加深对降水反演理论和算法的认识，提高降水反演的精度，还可以为FY-3G PMR即将开展的外场试验，提供设计思路。

英文摘要:

      By using the data of GPM KuPR，the accuracy of the FY-3G PMR prototype algorithm was evaluated. On this basis, the sensitivity analysis of precipitation rate retrieval was conducted with the initial value of R-Dm, phase, and the correction factor paramNUBF for NUBF. Firstly, the R-Dm of stratiform and convection were exchanged and DSD profiles, radar reflectivity factor profiles, and precipitation rate profiles were compared; Secondly, sensitivity experiments were designed to analyze the impact of phase misjudgment on the accuracy of precipitation rate retrieval; Finally, the sensitivity of paramNUBF to precipitation rate retrieval was evaluated by setting different paramNUBF. The results indicate that the FY-3G PMR prototype algorithm has good consistency in the inversion of precipitation structure and intensity distribution with KuPR, with a relative error of less than 10% and a correlation coefficient of better than 0.95. R-Dm is not sensitive to the retrieval of radar reflectivity factor profiles and precipitation rate profiles, but it is relatively sensitive to DSD profiles. Misjudgment of phase in bright band layer, especially between mixed phase states and solid or mixed phase states and liquid states, affects precipitation rate near the 0 degree layer and has little impact on ground precipitation rate. ParamNUBF is a highly sensitive factor, and the greater the difference from the true value, the greater the error of the precipitation rate profiles. Conducting sensitivity analysis on spaceborne radar precipitation rate retrieval algorithms can not only deepen understanding of precipitation rate retrieval theories and methods, improve the accuracy of precipitation rate retrieval, but also provide design ideas for the upcoming field experiments of FY-3G PMR.