雷州半岛“07.8”致洪特大暴雨的数值模拟  

Numerical Simulation of the "07.8" Flash-Flood-Producing Rainstorm in Leizhou Peninsula

作　　者：张羽[1,2] 牛生杰[1] 于华英[1] 张录青 劳汉琼 

机构地区：[1]南京信息工程大学中国气象局大气物理与大气环境重点开发实验室,江苏南京210044 [2]湛江市气象局,广东湛江524001 [3]韶关市气象局,广东韶关512026

出　　处：《大气科学学报》2010年第1期47-57,共11页Transactions of Atmospheric Sciences

基　　金：国家自然科学基金重点资助项目(40537034);公益性行业(气象)科研专项(GYHY(QX)2007-6-14)

摘　　要：利用中尺度非静力数值模式MM5,结合降水实况、红外卫星云图和雷达回波资料,对2007年8月8—11日发生在雷州半岛的致洪特大暴雨的形成机理进行了模拟分析和研究,包括雨量、动力热力特征、三维结构以及发展变化。结果表明,模拟雨带与实况位置吻合,中心强度与实况基本一致,强降水中心出现的时间略偏迟。此次强降水是由于受"帕布"减弱后的外围环流及其西南伸展的辐合槽带的天气形势影响,具有中尺度对流系统的特征。强降水落区与涡度场、散度场和垂直速度场有着较好的对应关系,强降水发生落区表现为明显的螺旋结构。在低层为正涡度区和负散度区,到中层后转为负涡度区和正散度区,强降水区域内低层辐合高层辐散,强烈的上升运动是导致强降水的主要原因。A flash-flood-producing rainstorm occurred in southwest part of the Leizhou Peninsula from 8th to 11 th August 2007 （ briefly ＂07.8＂ rainstorm）. The formation mechanism, precipitation, dynamic/ thermodynamic characters ,3D structure and development process of the＂07.8＂ rainstorm are investigated by the MM5 simulations in conjunction with the real-time precipitation, infrared cloud satellite images and radar echoes. Results show that the heavy precipitation simulation is in good accordance with the real location and central intensity of precipitation, but there are some time-delay and some underestimation of central amount of precipitation in the simulation in comparison with the reality. The rainstorm formed under influences of the outer circulation of weakening cyclone ＂Pabuk＂ and its southwestward- extended convergence trough, and possessed characters of meso-scale convective system. The location of heavy rain matched very well with vorticity, divergence, and vertical motion fields, and showed an apparent spiral structure;that is to say,there was positive vorticity and negative divergence at low level; negative vorticity and positive divergence in middle and high level over the heavy rainfall region,indicating that there was convergence in lower layer and divergence in higher layer. It is mainly such vigorous ascending motion that led to the heavy precipitation.

关 键 词：MM5模式 雷州半岛 致洪特大暴雨 数值模拟 形成机理 

分 类 号：P458.121.1[天文地球—大气科学及气象学]