EnKF循环同化相控阵雷达数据与变分雷达反演方法的对比研究:对一次台风外围龙卷个例的分析  

Comparison between the EnKF assimilating phased array radar observation and variational-based radar synthesis method:analysis for a tornado case

作　　者：王晨 赵坤[1] 朱科锋 傅佩玲 陈炳洪 杨正玮 WANG Chen;ZHAO Kun;ZHU Kefeng;FU Peiling;CHEN Binghong;YANG Zhengwei(School of Atmospheric Science,Nanjing University,Nanjing 210023,China;Nanjing Joint Institute for Atmospheric Sciences,Nanjing 210019,China;Guangzhou Meteorological Observatory,Guangzhou 511430,China)

机构地区：[1]南京大学大气科学学院,南京210023 [2]南京气象科技创新研究院,南京210019 [3]广州市气象台,广州511430

出　　处：《气象科学》2022年第1期1-11,共11页Journal of the Meteorological Sciences

基　　金：国家重点研发计划项目(2017YFC1501703);国家自然科学基金资助项目(41805015,42025501,41875053);灾害天气国家重点实验室开放课题(2020LASW-A01)。

摘　　要：针对2018年9月17日发生在广东省佛山市的一次台风龙卷过程,对比分析了EnKF和变分方法同化X波段相控阵雷达得到的风场结构。结果表明,EnKF方法和变分方法在同化了X波段相控阵雷达资料之后,都可以得到龙卷母体风暴的涡旋特征。相比之下,EnKF同化分析的涡旋强度更强,台风龙卷母体风暴及其周边三维风场的结构更加完整,与回波结构匹配更好。变分方法同化得到的流场不够连续,台风龙卷母体风暴的涡旋强度偏弱,弱回波区入流也明显偏弱,并不符合概念模型。而两种方法在没有同化相控阵雷达数据时,都无法产生龙卷母体风暴的流场特征。总体而言,相对于变分方法,EnKF同化系统在同化X波段相控阵雷达数据后可以产生更为合理的涡旋结构,台风龙卷母体风暴及其周边动力场结构更合理,这为以后X波段相控阵雷达的业务应用提供了思路。In this paper,based on the Ensemble Kalman Filter(EnKF)assimilation system and the advanced variational-based technique,the three-dimensional wind of a tornadic storm occurred in Foshan,Guangdong on September 17,2018 was examined by assimilating X-band phased array radar data.Results show that after assimilating X-band phased array radar data,both EnKF and variational-based technique can produce vortex characteristics of the tornado-parent storm.However,the vortex intensity produced by EnKF system is stronger,and the three-dimensional wind structure of tornadic storm and its surrounding area is more complete,which matches the reflectivity better.In contrast,the flow field obtained by variational-based technique is not continuous enough,and the vortex intensity is weak,which doesn t conform conceptual model.However,neither EnKF nor variational-based method cannot produce the flow field characteristics of tornado-parent storm when the phased array radar data was not assimilated.In general,compared with the variational method,EnKF assimilation system can produce more reasonable vortex structure after assimilating X-band phased array radar data,and the structure of tornadic storm and its surrounding dynamic field is more reasonable,which provides ideas for the future practical application of X-band phased array radar.

关 键 词：龙卷母体风暴 相控阵雷达 WRF ENKF 变分方法 

分 类 号：P445[天文地球—大气科学及气象学]