2008年6月广西锋前暖区暴雨过程分析  

Analysis on a Heavy Rain Process in a Warm Sector in Guangxi in June 2008

作　　者：赵金彪[1] 罗建英[1] 高安宁[1] 曾小团[1] 

机构地区：[1]广西气象台,南宁530022

出　　处：《热带地理》2010年第2期145-150,共6页Tropical Geography

基　　金：广西气象局科研项目"广西重大灾害性天气概念模型研究"(200725);"暴雨低涡发生;发展机理的分析研究"

摘　　要：利用常规观测资料、卫星TBB和NCEP再分析资料,对2008年6月8-13日持续性暖区暴雨的环流特征、影响系统及物理量变化进行了诊断分析,结果表明:本次暴雨过程是在高层200hPa出现环流型调整、500hPa贝加尔湖至新疆地区为弱阻高形势和地面锋面低槽的环境下产生的,主要影响系统有低层切变线和低涡;低空急流迅速建立、北抬,使低层风速辐合加强是产生锋前暖区暴雨的有利因素;广西的中尺度环境存在南北明显差异,可能是形成双雨带的主要原因;在切变线和低涡切变锋区上垂直运动结构有明显差异,低涡切变上低层辐合高层强辐散,上升运动更强烈;暴雨前相对湿度明显增大,湿层深厚,中高层相对湿度在降水减弱时率先出现下降趋势;水汽通量中心的出现与暴雨发生时段和暴雨落区较为对应;夏季风向北推进,华南地区发生经向风扰动,出现了季风涌,使南海的水汽和能量源源不断地传送到华南地区,为这次持续性暴雨提供有利条件。Circulation characteristics and influencing systems of a continuous rainstorm in a warm sector between June 8^th-13^th 2008 in Guangxi are studied by using the routine observational data, TBB and NCEP re-analysis data,. Results show that this rainstorm process was formed under a circulation adjustment at 200hPa and a weak block high over Baikal Lake - Xinjiang and a frontal trough at ground. The weather system included a low-level shear line and a low vortex. The wind speed convergence at low level strengthened by establishment of jet stream rapidly was the favorable factor of heavy rain happening in warm sector ahead of the front. There were a significant difference on the structure of vertical movement in the shear line and low shear vortex. The convergence on the lower level and strong divergence at high level led to increasing movement more strongly in shear vortex than in the shear line. The relative humidity increased markedly before heavy rain so that the wet layer was very deep, and in high layer the relative humidity first to downward when precipitation decreased. The period and falling-area of heavy rain were corresponding with the center of water vapor flux. There was a monsoon surge in southern china bringing water vapor and energy from South China Sea for this continuous rainstorm process.

关 键 词：中尺度对流 锋面低槽 低涡 暖区暴雨 季风涌 

分 类 号：P458.121.1[天文地球—大气科学及气象学]