中γ尺度大暴雨的生成与特征

Formation and Characteristics of Meso-γ-scale Heavy Rainfall

利用天气图、多普勒雷达回波图及FY-2C卫星云图资料对一次中γ尺度大暴雨天气过程进行天气背景、生成机制等方面分析,发现这次中γ尺度大暴雨具有如下特征:暴雨产生必须有充足的水汽源和输送路径;特定的地形有利于对流的生成和加深发展;稳定少动是孤立云团产生大暴雨的保证;地面辐合线、辐合区、逆风区的出现有利于暴雨定位和定量的精确预报;消散雷暴云的西侧或后部也能生成新的对流,并能形成强降水。

Based on the weather maps, Doppler radar echo map, as well as FY-2C satellite cloud images data, a meso-γ-scale weather background and formation mechanism were analyzed. It found that the meso-γ-scale heavy rainfall has these following characteristics： heavy rainfall must have adequate vapour source and transport path; specific terrain contributes for the formation and deepening of convection; stability with little movement guarantees a big rainstorm from isolated clouds; the emergence of ground convergence line, convergence and dead wind regions is in favor of the accurate prediction of the location and quantity of a rainstorm; new convection can form in the west side or the rear of dissipation thunderstorm clouds, and likely to produce heavy rain.