一类低涡切变型华南前汛期致洪暴雨的分析研究  

One Kind of Vortex Causing Heavy Rainfall during Pre-rainy Season in South China

作　　者：傅慎明[1,2] 赵思雄[1] 孙建华[1] 李万莉[2,3] 

机构地区：[1]中国科学院大气物理研究所,北京100029 [2]中国科学院研究生院,北京100049 [3]中国科学院寒区旱区环境与工程研究所,兰州730000

出　　处：《大气科学》2010年第2期235-252,共18页Chinese Journal of Atmospheric Sciences

基　　金：国家重点基础研究发展计划项目(编号:2009CB421401);国家自然科学基金资助项目40875021;国家自然科学基金资助项目40930951

摘　　要：采用2008年我国南方暴雨野外科学试验(SCHeREX)加密资料和NCEP再分析资料、FY-2C卫星TBB资料以及常规观测资料对广西致洪暴雨进行了研究。研究发现,西南涡是此次暴雨过程的直接影响系统,对流和降水主要发生在低涡的中部及其东南方。中高纬切断低压和副热带高压稳定维持,500hPa短波槽沿高原东侧南下,诱导西南涡向东南移入广西,这种情况并不太常见,这是由于槽后冷空气活跃,但路径偏西。受副热带高压西伸影响,低槽与西南低涡移动缓慢。在移入广西前西南涡一度减弱,但由于有明显的中、低纬系统相互作用存在,季风槽为本次暴雨输送了充沛的水汽,致使西南涡再度加强,引发暴雨。暴雨过程中中尺度对流云团活动频繁,强度大,降水强,有大约11个中尺度雨团缓慢移动。桂林的探空资料表明,暴雨区中低层温度层结多为中性,这可能是对流混合的结果,西南涡过境后,低层风场有明显变化,大气抬升凝结高度显著降低,对流有效位能(CAPE)由于释放而降低。在上述研究的基础上,本文提出了一类华南前汛期低涡切变型暴雨概念模型。Based on observations from the South China Heavy Rainfall Experiment（SCHeREX）and the reanalysis data from NCEP/NCAR,one kind of vortex with heavy rainfall during pre-rainy season in South China（1200 UTC 10 June-0000 UTC 13 June 2009）is analyzed,and the results are as follows.The southwest vortex（SWV）was the direct influencing system of heavy rainfall,convective activities and precipitation were always at the center or to the southeast of the southwest vortex.The rain areas moved from west to east with the southwest vortex and the short-wave trough.Convective clouds were active during this rainfall（some of them are meso-α-scale or meso-β-scale systems,respectively）and there were about 11 meso-scale rain clusters,which remained quasi-stationary or moved slowly.Neutral stratification,sometimes with thermal inversion,was located at the middle to low levels.After the southwest vortex moved out,wind at low levels changed remarkably,and the convective available potential energy（CAPE）decreased.The long persistence of cut-off low and subtropical high contributed to the stable maintenance of circulation.The short-wave trough at 500 hPa moved southward along the Tibetan Plateau,leading the southwest vortex to move southeastward to Guangxi.Influenced by the subtropical high,the trough was quasi-stationary,and after 0000 UTC 13 June,as the subtropical high retreated,the trough moved eastward.During the heavy rainfall,there were obvious interactions between middle and low latitude systems：the cold air was active,and the monsoon trough transported enough moisture to Guangxi,which enhanced the SWV.Based on the above researches,the schematic model of one kind of vortex causing heavy rainfall has been proposed.

关 键 词：云顶亮温西南涡华南前汛期季风槽 

分 类 号：P426[天文地球—大气科学及气象学]