GRAPES-3Dvar雷达资料直接同化对江淮暴雨数值预报影响的分析研究  

Analysis of the Impact of Radar Data Assimilation on the Numerical Forecast of Jianghuai Rainstorm by Using GRAPES-3Dvar

作　　者：李媛[1] 刘健文[2] 董佩明[2] 刘红亚[3] 

机构地区：[1]西安通信学院,西安710106 [2]北京航空气象研究所,北京100085 [3]中国气象科学研究院,北京100081

出　　处：《气象》2011年第4期403-411,共9页Meteorological Monthly

基　　金：十一五国家科技支撑计划项目(编号:2006BAC02B00)资助

摘　　要：使用具备多普勒雷达资料直接同化功能的GRAPES-3Dvar同化系统,对2007年7月江淮流域连续性暴雨过程中4个个例进行了数值预报试验,结果表明多普勒径向速度以及基本反射率因子的直接同化可以有效改进中尺度降水数值预报的效果。对7月3日雷达资料联合同化以及单独同化对分析和预报影响的进一步分析显示,联合同化能够有效改善初始分析场中的风场和湿度信息,激发模式降水,减小SPIN-UP现象,中尺度系统降水的发生发展以及强度、走势和落区的预报得到较为准确的表征,显著改善了中尺度强降水数值预报效果。径向速度的直接同化主要贡献表现在风场上,能够在初始场中增加气旋性涡旋等中小尺度风信息,改善三维风场分析。反射率直接同化的主要影响体现在湿度场上,改进了初始场中的湿度参数,对降水预报影响明显。In this paper,four cases on the Yangtze-Huaihe River Valley（Jianghuai for short） during continuous rainstorm process in July 2007 are chosen for numerical prediction experiments using the GRAPES- 3Dvar model with radar direct assimilation function.The results have shown that the direct assimilation of the Doppler radial velocity,as well as the basic reflectivity factor can effectively improve the numerical prediction effects of mesoscale precipitation.The further analysis of the joint and the separate assimilation of radar data assimilation on July 3 shows that;Joint assimilation can improve.the initial analysis of the wind field and humidity information,stimulate model precipitation,reduce the spin-up phenomenon.Hence the mesoscale precipitation＇s occurrence and development as well as the strength,movements and distribution are more accurately forecasted,and the effects of mesoscale numerical forecast of heavy precipitation are significantly improved.The main contribution of radial velocity direct assimilation is in the wind field, which can increase small and medium-scale wind information such as cyclonic vortex in the initial field,improve the analysis of three-dimensional wind field.The main impact of reflectivity＇s direct assimilation is in the humidity field,which improves the initial humidity field parameters,and impacts significantly the precipitation forecast.

关 键 词：多普勒雷达 直接同化 GRAPES-3Dvar 数值预报 江淮暴雨 

分 类 号：P457.6[天文地球—大气科学及气象学]