雷达径向风和反演风联合同化在台风灿都(2010)数值预报中的研究  

A Combined Radar Data Assimilation Strategy of Radial Velocity and Retrieved Wind and Its Impact on the Forecasting of Tropical Cyclone Chanthu(2010)

作　　者：李昕[1,2] 王元[2] 明杰[2] 梅海霞[1] 王文兰[1] 周嘉陵[1] 

机构地区：[1]江苏省气象科学研究所,南京210009 [2]南京大学大气科学学院中尺度灾害性天气教育部重点实验室,南京210093

出　　处：《气象》2016年第6期649-663,共15页Meteorological Monthly

基　　金：“十二五”国家科技支撑计划(2014BAG01B01);国家重点基础研究发展计划(973计划)(2015CB452801);江苏省青年气象科研基金(Q201514、Q201407);山东省气象科学研究所开放研究基金项目(SDQXKF2015M10);江苏省科技支撑计划项目(BE2013730);江苏省气象科研基金项目(KZ201502,KZ201202)共同资助

摘　　要：基于WRF模式及其Hybrid集合-变分同化系统,比较研究了雷达径向速度(V_r)同化和T-TREC(Typhoon-Tracking radar echoes by correlation)反演风同化对台风灿都(2010)分析和预报的影响。为了探索最适合登陆台风预报的雷达资料同化策略,在研究V_r循环同化和T-TREC循环同化的基础上,考虑到两种雷达风场资料各自的优势,提出了合理利用两种雷达风场资料的联合同化策略,即在循环同化的首次分析中同化T-TREC风,而在之后的分析中同化V_r资料。研究三种不同的雷达资料同化策略发现,V_r直接同化虽能改善台风分析和预报,但其依赖于较多的同化次数,这会导致确定性预报的启动时间较晚,不利于台风业务预报。相比之下,由于T-TREC资料观测范围远、风场结构完整,T-TREC循环同化策略只经过较少次数的同化分析即能显著改善台风强度预报;然而受T-TREC资料自身反演误差的影响,增加同化次数反而不利于提高预报效果。当联合利用这两种雷达风场时,联合同化策略在不同同化时间窗下的预报表现均最优。Based on WRF model and the Hybrid ensemble-3Dvar data assimilation system,this study compares radar radial velocity（V_r） assimilation with T-TREC（Typhoon-Tracking radar echoes by correlation） retrieved wind data assimilation and their impacts on the analyses and forecasts of tropical cyclone（TC） ＂Chanthu（2010）＂.In addition to the cycling strategy of V_r assimilation and T-TREC wind data assimilation,a combined radar data assimilation strategy is proposed,which assimilates T-TREC winds at the first cycle and assimilates V_r data during the rest cycles.Concerning the respective advantages of two types of radar wind,the new cycling strategy aims at exploring the suitable radar data assimilation strategy for the forecasting of landfalling TCs.Comparing three different cycling strategies,the cycled assimilation of V_r data requires more analysis cycles,which leads to delayed starting time for the deterministic forecast.By contrast,the assimilation of T-TREC data produces better analyses and intensity forecasts than the assimilation of V_r data during the earlier assimilation,due to the larger data coverage and more complete wind fields for TC circulation.However,as the T-TREC winds contain retrieved errors,the increase of analysis cycles leads to degraded TC forecast.When the two types of radar wind data are jointly used,the combined radar data assimilation strategy provides favorable forecast results no matter how long the analysis cycles are.

关 键 词：台风 Hybrid集合-变分同化 径向速度同化 T-TREC反演风同化 雷达风场联合同化 

分 类 号：P456[天文地球—大气科学及气象学]