中尺度对流系统影响西南低涡持续性暴雨的诊断分析  

Diagnostic Analysis of Mesoscale Convective Systems Influence on Sustained Rainstorm Caused by Southwest Vortex

作　　者：胡祖恒[1] 李国平[1] 官昌贵 王红丽 

机构地区：[1]成都信息工程学院大气科学学院,成都610225 [2]纳溪区气象局,泸州646300 [3]贵州省气象局,贵阳550002

出　　处：《高原气象》2014年第1期116-129,共14页Plateau Meteorology

基　　金：国家重点基础研究发展计划(973)项目(2012CB417202);公益性行业(气象)科研专项(GYHY201206042)

摘　　要：利用加密自动站降水资料、FY-2E卫星云顶相当黑体温度TBB资料和NCEP再分析资料,对2010年7月16-18日四川盆地持续性暴雨天气过程中的西南低涡及伴随发展的中尺度对流系统(MCS)进行了分析。结果表明,500 hPa高空槽、700 hPa中尺度切变线和暖湿气流为MCS的发生提供了良好的环境条件;地面降水时空分布具有明显的中尺度特征,MCS是造成暴雨的重要原因;暴雨中心集中在TBB冷云区或边缘梯度密集带。在西南低涡发展过程中,MCS有利于激发上升气流,中低层的上升气流和正涡度配合利于热量和水汽垂直输送,高层的辐散进一步促使MCS的发展。水平涡度平流和涡度垂直输送项的配置影响上升气流和涡旋系统的发展,MCS对西南低涡的移动有一定的引导作用。有无MCS伴随发展时,对流活动对热量和水汽的输送能力迥异。Based on the AWS precipitation data, black body temperature at cloud top data of FY - 2E and NCEP final-analysis data, the southwest vortex which caused sustained rainstorm in the Sichuan basin during 16 --18 July 2010 and it companied with the mesoscale convective systems （MCS） were analyzed. The results show that ： 500 hPa upper trough, 700 hPa mesoscale shear line and warm and humid air causing a favorable conditions for the development of MCS. The spatial and temporal distribution of surface rainfall obviously showed me- soscale characteristics, the MCS is the important reason for heavy rainfall. The central of precipitation emerged mainly in the cold cloud cluster area or intensive edge of TBB. In the developing process of southwest vortex, MCS is benefit for motivating updraft, updraft in the low and middle level and positive vorticity promote to trans- port heat and water vapor, divergence in the high-level further promote the development of MCS. The configura- tion of horizontal vorticity advection and the vertical transportation of vorticity influence on the development of the rising airflow and vortex system, MCS has a certain extent guiding function for the motion of southwest vor- tex. With MCS accompanied or not, the ability of convection conveying heat and water vapor is significant dif- ferent.

关 键 词：西南低涡 湿Q矢量 视热源 视水汽汇 中尺度对流系统(MCS) 

分 类 号：P458.121[天文地球—大气科学及气象学]