2017年8月克州一次局地强降水天气过程分析

Analysis of a Local Heavy Rainfall Process in Kezhou in August 2017

摘要: 利用常规观测、T639、EC数值预报、FY2D卫星等资料，从大尺度环流、影响系统、高低空配置、水汽条件及物理机制等方面分别对2017年8月3~4日出现的强降水，从大尺度环流背景及物理量场进行了分析，结果表明：此次降水发生在南亚高压为双体型的大尺度环流背景下，500 hPa影响系统为咸海至巴湖的低槽，配合低层有明显的风幅合，物理量场表现为，暴雨发生区比湿最大值位于850 hPa，为8~10 k/kg，水汽通量散度场在阿图什市及阿合奇县一带，幅合中心最强，为−24 × 10⁻⁷ g/(cm²•hPa•s)，充足的水汽供应，强烈的上升运动，不稳定能量的释放，是此次强降水出现的重要条件。

Abstract: Based on the data of conventional observation, T639, EC numerical forecast and fy2d satellite, the heavy rainfall on 3th-4th August, 2017 was analyzed from the aspects of large-scale circulation, influence system, high and low altitude configuration, water vapor condition and physical mechanism. The results show that the precipitation occurred in 500 hPa under the background of large-scale circulation with double South Asia high. The impact system is a low trough from the Aral Sea to the Ba Lake, with obvious wind amplitude and convergence in the lower layer. The physical quantity field shows that the maximum specific humidity in the rainstorm area is located at 850 hPa, 8 - 10 k/kg, and the water vapor flux divergence field is located in the area of Atushi City and Aheqi County, with the strongest amplitude and convergence center, which is −24 × 10⁻⁷ g/(cm²•hPa•s). Sufficient water vapor supply, strong upward movement and release of unstable energy are the important conditions of this heavy rainfall.