准静止锋背景下的贵州两次暴雨天气过程对比分析

Comparative analysis of two torrential rain in the background of Quasi Stationary Front in Guizhou

该文利用常规探空资料、地面观测资料及NCEP1.0°×1.0°再分析资料,对2014年6月9日08时—10日08时(简称9日,下同)和6月26日08时—27日08时(简称26日,下同)贵州出现的两次暴雨过程进行对比分析,结果表明:①两次暴雨均集中分布在20时准静止锋附近及其偏南一侧,跨越纬度约1°,其分布与环流垂直结构有较好的对应关系。②9日暴雨落区主要集中在贵州西南部,呈团状分布,降水时段比较集中;26日暴雨落区位于贵州南部一线,呈不连续的带状分布,降水时段偏长;9日08时准静止锋位于滇东,26日08时准静止锋位于贵州东北部,结合两次暴雨落区与准静止锋位置变化,暴雨落区与滇黔准静止锋摆动有极大的关系。③9日暴雨的水汽主要来源于孟加拉湾西南气流;26日暴雨的水汽受孟加拉湾偏西气流和副高外围西南气流共同作用。9日暴雨位于反气旋底后部东南气流与偏西气流交汇处,26日暴雨发生在低涡前部偏西南气流与偏南气流的交汇处。④9日暴雨垂直上升运动大值中心位于贵州西南部,26日暴雨垂直上升运动大值中心分别位于贵州西南部和东南部,暴雨落区与垂直上升运动大值中心有较好的对应关系;9日暴雨在贵州西南部上空存在低层辐合—中高层辐散—高层辐合的配置,26日暴雨在贵州东南部上空存在低层辐合—中高层辐散—高层辐合的配置,高、低空抽吸作用对暴雨发生提供了有利条件。

This paper comparative analyzes two torrential rain processes occurred at two periods by using the conventional sounding data, ground observation and the NECP 1°×1°reanalysis data, one is from 08 ∶00 on 9 June to 08 ∶00 on 10 June, another is from 08 ∶00 on 26 June to 08 ∶00 on 27 June in 2014. The main results show that both of the two torrential rain processes occurred near the south side of the quasi stationary front across latitude about 1 °. Besides, the torrential rain area with the vertical structure of circulation has a good correspondence. Secondly, the process occurred on 9 June is located in the southwest of Guizhou, the precipitation period is relatively concentrated with mass distribution located in the southwest of Guizhou . The process occurred on 26 June is located in the south of Guizhou, with a discontinuous band distribution located in the south of Guizhou. The precipitation period is more longer. Torrential rain on 9 days was influenced by quasi stationary front located in the eastern Yunnan at 08 ∶00, torrential rain on 26 days was affected by quasi stationary front in the northeastern Guizhou at 08 ∶00, Combined two torrential rain area with the position change of quasi stationary front, we can see that between the area of heavy rain and the swing of Dianqian quasi stationary front have a great relationship. Thirdly, torrential rain water vapor conveyor belt of torrential rain on 9 days is the west southerly airstream come from the Bay of Bengal. Storm water vapor transmission with two paths of torrential rain on 26 days, one of them is the westerly air current from the bay of Bengal, the other is the southwest airflow along the subtropical high peripheral deliverto the southeast of Guizhou province. The torrential rain on 9 days was located at the junction of the southeast air and the westerly airflow at the rear of the anti-cyclone, the torrential rain on 26 day occurred at the intersection of the low vortex and the southwest airflow and the southerly airflow. Fourthly, the high value center of the vertical rising motion of the torrential rain on 9 days is located in southwest Guizhou, while the center of the vertical speed of heavy rain on the 26th day is located in the southwest of Guizhou and the southeast of Guizhou. Torrential rain on 9 days performance over southwestern Guizhou has the structure of lower convergence-middle-upper level divergence-high-level convergence, torrential rain on 26 days over the southeast Guizhou has the structure of lower convergence-middle-upper level divergence-high-level convergence, the strong suction function between the lower and the upper provides a favorable condition for the occurrence of heavy rain.