利用NECP再分析资料(1°×1°,逐6 h)、FY-2G卫星资料、多普勒天气雷达以及自动气象站降水资料,分析2015年9月15日—16日云南省华坪和昌宁发生的局地性强降水过程.结果表明:本次降水为西太平洋副热带高压外围气流影响下产生的,降水前华坪及昌宁的水汽通量值分别为4、6 g·cm^(-1)·h Pa^(-1)·s^(-1),水汽通量散度值分别为-3×10^(-7)、-2×10^(-7)g·cm^(-2)·h Pa^(-1)·s^(-1),在华坪和昌宁出现明显的气流辐合,水汽条件和动力条件远达不到云南省强降水过程发生的条件;在红外云图上2个区域都出现了2次椭圆状的β中尺度对流云系的发生发展减弱过程;在雷达图上,华坪县强降水时段维持高反射率因子和高回波顶高特征,多个时次速度图上出现了逆风区特征,以及在3.4°仰角速度图上持续出现辐散特征,昌宁县出现了持续性的“列车效应”,35^45 d Bz强回波中心都位于强降水区域,是强降水持续了8 h的主要原因.
Based on NCEP reanalysis data( 1°× 1°), FY-2G satellite data, Doppler radar data and precipitation data of automatic weather stations, severe convective rainfall occurring in Huaping and Changning have been analyzed on 15th and on 16th in September 2015.The results show that the western Pacific subtropical high is the main cause of the weather change ,with the water vapour Fluxesof four and six g · cm-1 · hPa-1 · s-1 , and the water vapor flux divergence of -3×10^-7,-2×10^-7 g · cm-1 · hPa-1 · s-1 before raining,the airflow convergence occurring in Huaping and Changning, and water vapor condition and dynamic conditions is far less than the strong precipitation process.Both of the areas of rainstorm experienced a process of generation and development about β -Mesoscale Convective System on satellite.In Huaping ,with high reflectivity and high echo top features, with a number of times when the velocity map presenting a upwind characteristic, and in the 3.4 degree elevation velocity continuous divergence characteristics.In Changning,the main reason for heavy rain lasting 8 hours was persistent "train effect" ,with 35-45 dBz strong echo center located in the region of heavy rain.