“03.7”江淮梅雨锋暴雨中尺度系统的数值模拟研究  

DIAGNOSTIC ANALYSIS AND NUMERICAL SIMULATION OF THE MESO-SCALE SYSTEM DURING "03.7" MEIYU FRONTAL RAINSTORM EVENT

作　　者：王欢[1] 周军[2] 雷娟[3] 

机构地区：[1]江西省气象台,江西南昌330046 [2]南京信息工程大学大气科学系,江苏南京210044 [3]新余市气象局,江西新余338025

出　　处：《气象与减灾研究》2006年第2期32-38,共7页Meteorology and Disaster Reduction Research

基　　金：国家重点基础研究发展规划项目(G1998040907-02-01)

摘　　要：应用非静力中尺度数值预报模式MM5,对2003年7月4～5日的江淮梅雨锋暴雨过程进行了24h模拟,结果较好地再现了中β尺度暴雨系统的发展过程。进而利用时空分辨率较高的模式输出资料,对与这次暴雨过程相伴随的中β尺度系统的结构、生消变化状况及其可能的形成机制进行了研究。研究结果表明,梅雨带上强烈发展并东移的多个中β尺度对流系统,是造成这次江淮暴雨最直接的影响系统。在对流系统发展初期,锋生强迫下的次级环流加强了锋生区附近大气低层的风向风速辐合,它与对流活动有正反馈作用。对称不稳定可能是中β尺度系统发生发展的一种重要机制,在中β尺度系统发生的弱对流不稳定区,湿位涡的斜压项mpv2起了主导作用。Heavy rainfall event during 4th-5th July,2003 is diagnosed by using the conventional observational datasets and infrared satellite pictures,and it occurs under the influence of the westerly trough at 500hPa level,the shear line at 850 hPa level,the meso-scale low vortex system and the stationary front on surface while large-scale circulation is stable. Based on the meso-scale model MM5,the numerical simulation of the heavy rainfall event during 4th-5th July,2003 is carried out.Simulated results show that the development of the meso-scale rainstorm system is well described.By analyzing high resolution model output,the evolvement of meso-β-scale system along with rainstorm and its mechanism are investigated.It shows that: MCSs propagated eastwardly,which develop on Meiyu front,is the direct influent system of the rainstorm.At the early stage of the development of MCS,secondary circulation forced by frontogenesis intensifies the convergence of low level air over the frontogenesis region,which makes a positive feedback on convective activity.Symmetric stability is the possible mechanism of meso-β-scale system.Over the convectively unstable area,baroclinic item of moist potential vorticity(mpv2) is the dominant factor.

关 键 词：梅雨锋暴雨 数值模拟 中β尺度系统 对称不稳定 次级环流. 

分 类 号：P458.1+21.1[天文地球—大气科学及气象学] P456.7