致洪暴雨过程中尺度涡旋的结构和准平衡特征分析  

Structure and quasi-balanced feature analyses of the mesoscale vortex during a flash-flood-producing rainstorm process

作　　者：谭伟才 钟玮 陆汉城 李启华 TAN Weicai;ZHONG Wei;LU Hancheng;LI Qihua(College of Meteorology and Oceanography,Defense University of Science and Technology,Nanjing 211101,China;No.75839 of People s Liberation Army,Guangzhou 510510,China)

机构地区：[1]国防科技大学气象海洋学院,江苏南京211101 [2]中国人民解放军75839部队,广东广州510510

出　　处：《大气科学学报》2018年第1期25-35,共11页Transactions of Atmospheric Sciences

基　　金：国家自然科学基金资助项目(41275002;41175054);国家自然科学基金重点资助项目(41230421)

摘　　要：利用2008年6月广西致洪暴雨过程高分辨率数值模式资料,分析引起暴雨的中尺度涡旋在移动和持续性发展过程中其内部结构的演变以及系统的动力学特征。研究结果表明,中尺度涡旋是导致此次广西暴雨的主要系统,其发展移动过程中伴随有强烈上升运动的深厚湿对流,并在中高层持续形成明显的暖心结构。此次涡旋系统移动过程可分为涡旋南移和涡旋东移两个阶段,由于受到环境场的影响,涡旋中心区域动量、热量和水汽的再分配为其持续性发展提供有利条件。同时诊断分析表明,涡旋内部存在具有继发特征的长时间维持的组织化深厚湿对流系统,以强非地转分量为特征的超地转流,并表现出涡散运动共存且同量级的特征,具有典型的准平衡特征。Based on a high resolution numerical simulation of the flash-flooding rainstorm process in Guangxi in June 2008,the evolution of the inner structure and dynamical features of the mesoscale vortex,which caused the heavy rainfall,have been investigated in terms of movement and continued development process.By means of synoptic analysis,it is found that the mesoscale vortex was the main system leading to the rainstorm in Guangxi.The core of the rain band at different times mainly lied in the eastern part of the vortex within the range of 400 km,and the track and intensity of the rain band coincided with those of the vortex.The structure of the mesoscale vortex was especially distinct on 700 hPa,with the horizontal size ranging from 600 to 900 km.In addition,its move path could be divided into two stages:the southward moving stage and the eastward shifting stage.Using the high-resolution model output data to analyze the inner subtle dynamic and thermodynamic structures of the mesoscale vortex,it is shown that strong ascending motion existed in the vortex center,which was quite beneficial to the formation of organized deep and moist convection systems.When the vortex reached its intensity peak,the vertical size of these convection systems could run through the entire troposphere,with the rotational motion and potential motion reaching the same magnitude.During the vortex s development process,the release of latent heat showed that there was an obvious warm core at the middle and high levels of the vortex center,and the stronger the vortex grew,the more distinct it became.Meanwhile,upward vertical transportation of warm wet flow,which was caused by strong convergence at low levels,signified that the vortex center attained high humidity.Influenced by the environment in the vortex s movement and development process,the redistribution of momentum,heat and moisture in the vortex center area took place as follows:(1)As the vortex moved southward along the Yunnan-GuizhouPlateau,its central pressure decreased and a uniform ho

关 键 词：暴雨 中尺度涡旋 结构特征 准平衡特征 

分 类 号：P458.121.1[天文地球—大气科学及气象学]