基于实测雨滴谱数据的微波链路和天气雷达降水估计关系研究  

Research on Precipitation Estimators of Microwave Link and Weather Radar Based on Raindrop Size Distribution Data

作　　者：张鹏 刘西川[2] 周则明 宋堃[2] 杨平吕 ZHANG Peng;LIU Xichuan;ZHOU Zeming;SONG Kun;YANG Pinglü(Centre of Teaching and Research Support,Army Engineering University of PLA,Nanjing 210014;College of Meteorology and Oceanology,National University of Defense Technology,Changsha 410005)

机构地区：[1]陆军工程大学教研保障中心,南京210014 [2]国防科技大学气象海洋学院,长沙410005

出　　处：《气象》2021年第7期843-853,共11页Meteorological Monthly

基　　金：国家自然科学基金项目(41975030);江苏省自然科学基金项目(BK20181337)共同资助。

摘　　要：利用南京地区连续两年夏季的实测雨滴谱数据,分析了雨滴谱和降水特征,区分降水类型计算了微波链路衰减系数与雨强的关系(雨衰关系)和雷达反射率因子与雨强(Z-R)的关系,所得关系与ITU-R雨衰模型和常用Z-R关系均有差异,其中对流性降水中的Z-R关系为Z=161.63R^(1.55),层状云降水中为Z=227.23R^(1.53)。在两次不同类型降水过程中利用微波链路和天气雷达反演降水,结果表明:使用ITU-R雨衰关系反演降水存在高估层状云降水、低估对流性降水的问题,使用常用Z-R关系反演降水存在明显低估降水的问题,而使用雨滴谱计算的雨衰关系和Z-R关系反演的降水与雨量计实测降水更加一致,平均绝对误差降低,相关性明显提高。说明使用实测雨滴谱数据计算得到的本地化的雨衰关系和雷达Z-R关系,能够提升定量测量降水的准确性。To improve the quality of quantitative precipitation estimation(QPE),the characteristics of local precipitation are analyzed using the measured raindrop size distribution(DSD)data of Nanjing Area in two consecutive summers.The precipitation estimators(PEs)including the relationship of microwave rainfall attenuation and rain rate and the relationship of weather radar intensity and rain rate are calculated based on the DSD data.The relationships obtained are different from ITU-R rain attenuation relationships and commonly used Z-R relationships.The radar Z-R relationship for convective precipitation is Z=161.63R^(1.55)and Z=227.23R^(1.53)for stratiform precipitation.Using these PEs,the rain rate distributions in two rainfall cases of different types are retrieved with a microwave link and a weather radar.The results are as follows.The rainfall is overestimated in stratiform precipitation and underestimated in convective precipitation when using ITU-R rain attenuation relationship.The rain rates are obviously underestimated when using commonly used Z-R relationship.The rain rates retrieved with the rain attenuation relationship and the Z-R relationships obtained from the DSD data are more consistent with the rain rates measured by the rain gauges.The mean absolute errors are reduced,and the correlations are significantly improved.The results show that the accuracy of QPE can be improved effectively by using the local PEs calculated by the DSD data.

关 键 词：雨衰关系 Z-R关系 雨滴谱 定量测量降水 微波链路 天气雷达 

分 类 号：P414[天文地球—大气科学及气象学]