一次华南暴雨降水过程的模拟分析

应用显式双参数微物理过程的β中尺度非静力平衡模式,利用福州市1998年6月9日16时的加密探空资料进行了3小时的数值模拟。在模拟过程中形成的上升、下沉气流的有利配置,使得其前部的辐合区域丰富的水汽源源不断地往高层输送,从而维持了长时间降水,是一次超级单体过程。分析了五种相变过程的垂直分布情况及其对水成物和大气温度的贡献,凝结对这两者的贡献占最主要位置。在研究了降水粒子的比浓度和比质量的源汇项后,得出此次降水过程以暖雨过程开始,随后出现霰融化成雨滴并通过碰并云滴增长的冷雨过程。3小时的模拟降水范围超过了100km,累积降水达到了32mm,与附近站点的阶段降水实况比较接近。

Numerical Simulations of a Heavy Rainfall Case in South China

Using a double-parameter non-hydrostatic elastic three-dimensional model with detailed microphysicalprocesses, the authors simulate the heavy rainfall event in South China which occurred on 9 June 1998 andlasted for more than 3 hours. This case is a supercell, and the upward and downward drafts interact witheach other, which transfers rich water vapor at the converging position to upper levels, and the two draftstogether maintain the convective course. The vertical heating profiles and contributions to water matterof five kinds of micro-phase processes are revealed quantitatively in the results. Condensation releases themost heat, which is more than that of the absorption by evaporation and melting. The rain particles firstcome from the autoconversion of cloud particles, the warm-rain process; later from the cold-rain process,the melting of grauple particles. The precipitation intensity reaches 75 mm h-1 while its efficiency remainshigh. The total amount of rain is 32 mm, a value close to the observations of nearby stations.