2014年6月19—20日吉安市的对流性暴雨分析

Analysis of a Convective Rainstorm on June 19—20,2014 in Ji'an City

利用常规观测资料、FY-2E红外云图及其反演产品TBB、多普勒雷达资料、地面加密自动站等资料,分析了2014年6月19—20日吉安市对流性暴雨天气过程。结果表明:在西风槽东移和中高层干侵入背景下,由地面中低压、地面中尺度辐合线触发形成的中尺度对流系统。对流性暴雨产生在中尺度对流云团发展强盛到成熟阶段,强降雨落区位于TBB低温中心附近及后侧梯度大值区。雷达回波图有明显的反射率因子核心,在降水发生时,最大反射率因子高度和单体质心高度的明显降低,伴随着降水强度增强。

Using the data of conventional observation, cloud imagery from FY-2E satellite and its retrieved product of TBB, Doppler radar observation and intensive surface automatic weather stations, we analyzed a convective rainstorm that took place on June 19 to 20, 2014 in the city of Ji＇an. The result is presented as follows. Under the background of the eastward progression of a westerly tough and dry intrusion at the middle and high levels, a mesoscale convective system was formed due to the triggering effect of a mesoscale low and a convergence line at the surface. The convective rainstorm was resulted when the mesoscale convective cloud cluster developed to its maturing phase. The area of intense rain was located near the center of a low-TBB and a large-gradient area at its rear. On the radar echo, there was a well-defined core of reflectivity and when the rain took place, the heights of maximum reflectivity and mass core of cells dropped significantly in association with rain intensification.