一种X波段相控阵天气雷达反射率因子订正算法  

A reflectivity factor correction algorithm for X-band phased array

作　　者：余乐福 姚聃 肖艳姣[2,3] 董元昌 YU Lefu;YAO Dan;XIAO Yanjiao;DONG YuanChang(Foshan Meteorological Service,CMA Tornado Key Laboratory,Foshan 528300;CMA Meteorological Observation Center,Beijing 100081;Hubei Key Laboratory for Heavy Rain Monitoring and Warning Research,Institute of Heavy Rain,CMA,Wuhan 430205;Heavy rain and Drought-Flood Disaster in Plateau and Basin key Laboratory of Sichuan Province,Chengdu 610072)

机构地区：[1]广东省佛山市气象局中国气象局龙卷风重点开放实验室,佛山528300 [2]中国气象局气象探测中心,北京100081 [3]中国气象局武汉暴雨研究所暴雨监测预警湖北省重点实验室,武汉430205 [4]高原与盆地暴雨旱涝灾害四川省重点实验室,成都610072

出　　处：《暴雨灾害》2023年第4期446-454,共9页Torrential Rain and Disasters

基　　金：国家重点研发计划项目(2018YFC1507303);广东省气象局科学技术研究面上项目(GRMC2021M27)。

摘　　要：不同雷达观测相同目标的反射率因子差异会影响雷达组网应用效果,对无波束阻挡的X波段雷达而言,这种差异主要由雷达定标偏差和信号衰减引起,其中衰减包含降水导致的衰减以及天线罩水膜导致的衰减。为了订正定标偏差、天线罩水膜衰减以及降水衰减,设计了一个基于相控阵雷达组网的订正方法。首先,将天线罩水膜导致的衰减看作定标偏差的一部分,使用组网衰减订正算法做初次衰减订正;然后,通过构建一个雷达网观测偏差函数,使用梯度下降法求解各雷达之间的定标偏差;最后,将订正了定标偏差的原始反射率因子再次使用组网衰减订正算法进行二次衰减订正。对上述订正方法,用于广东省佛山市7部X波段相控阵天气雷达探测的一次冷空气降水过程进行检验。结果显示,传统的PIA(Path-integrated attenuation)算法订正结果与广州S波段天气雷达观测结果相关系数为0.53,均方根误差为9.0 dB,而该算法这两项数值分别为0.64和8.4 dB,优于PIA;在台风外围的局地强降水过程中也得到了相同的结论。The difference between reflectivity factors observed by different radars observing the same target affects the performance of the multi-radar mosaic.For X-band radars without beam blocking,this difference is mainly caused by calibration deviation and signal attenuation due to rain and wet radome.To correct these errors,a new correction algorithm for network phased array weather radars is designed.In this new algorithm,we first regarded the attenuation due to water film on the radome as part of the calibration deviation,and used the network attenuation correction algorithm to make an initial attenuation correction.Then,an observation deviation function of the radar network is designed,which used the gradient descent method to solve the calibration deviation issue between different radars.Finally,a secondary attenuation correction,which used the network attenuation correction algorithm,is applied to the original reflectivity factor after calibration deviation correction.In this study,a network consisting of seven X-band phased array weather radars in the Foshan city of Guangdong province is used to verify the new correction algorithm.For a rainfall event associated with cold air,a correlation coefficient of 0.53 between the reflectivity factor corrected with the traditional path-integrated attenuation(PIA)algorithm and the reflectivity factor observed by an S-band weather radar in Guangzhou was obtained,with a root mean square error of 9.0 dB.While those between the new correction algorithm and the S-band radar are 0.64 and 8.4 dB,respectively,with both being better than PIA.A similar performance was also achieved in a typhoon outer rain-band rainfall event analysis.

关 键 词：相控阵天气雷达 衰减订正 定标偏差 湿天线罩衰减 雷达组网 

分 类 号：P412.25[天文地球—大气科学及气象学]