华南暖区一次暴雨中尺度系统的数值模拟  

Numerical Simulation of Mesoscale System of a Rain Storm in Warm Section of Southern China

作　　者：覃丽[1] 寿绍文[2] 夏冠聪 刘泽军[4] 

机构地区：[1]广西区气象台,广西南宁530022 [2]南京信息工程大学大气科学学院,江苏南京210044 [3]广东省中山市气象局,广东中山528400 [4]广西气象减灾研究所,广西南宁530022

出　　处：《高原气象》2009年第4期906-914,共9页Plateau Meteorology

基　　金：广西壮族自治区气象科研计划项目(桂气科200725)资助

摘　　要：为深入了解华南暖区暴雨产生的机制,首先利用观测资料和卫星云图对2005年5月9日华南暖区一次暴雨过程进行天气分析,然后利用MM5V3.6数值模式对该次暴雨过程进行了模拟,利用模拟的输出结果分析了中尺度系统的结构特征和成因。结果表明,这次华南南部暖区的暴雨区出现在低空急流出口区左侧的辐合区与高空急流入口区右侧的辐散区相迭置的区域;中尺度对流云团是暴雨的直接影响系统,系统中心上空偏南气流强烈垂直上升与在系统以南对流层高层下沉的气流构成垂直闭合反环流,低层气流风速辐合对暖区暴雨系统的形成和发展起决定性的作用。较大的螺旋度可能是暖区暴雨及其中尺度系统发生、发展的一种重要机制,可用来判断降水系统的形成和移动。In order to understand the rainstorm process in warm section over southern China, the rainstorm occurring on May 9, 2005 is analyzed using the synoptic observation data and satellite image firstly. Then the numerical simulation of the rainfall is conducted by using MM5V3.6 model. Based on the outputs of successful simulation, the structure and cause of the mesoscale rainstorm system are studied. Results show that the divergence generated on the right side of the upper level jet entrance region overlapping the convergence generated on the left side of lower level jet exit region in southern part of South China leads to the heavy rain happening in the warm section. The mesoscale convective clouds are direct affecting system of the rainstorm. The southerly flow vertically ascends strongly over the rainstorm system and the ascending draft forms a meridional vertical counter-circulation with the downdraft in upper troposphere on the southern side of the system in cross-section along longitude. The velocity convergence of lower level flow plays a crucial role in formation and development of the heavy rain system of warm sector. It is indicated that the higher rotational helicity might be one important mechanism for the rainstorm and can be used to judge the development and movement of the rainstorm system.

关 键 词：暖区暴雨 数值模拟 中尺度系统 螺旋度 

分 类 号：P458.1[天文地球—大气科学及气象学]