微下击暴流的特征及其数值模似

CHARACTERISTICS AND NUMERICAL SIMULATION OF MICROBURST

中文关键词:  微下击暴流  特征  数值模拟

英文关键词:Microbursts  char acteristis  Case study  Numerical simulation

中文摘要:

      文中概述了微下击暴流的特征,研究了1997年7月22日发生在北京地区的一个湿型微下击暴流的多普勒速度场结构;使用非静力全弹性中-γ尺度模式,模拟了这个湿型微下击暴流线的主要结构和演变过程,与雷达实测结果吻合较好。结果表明:在背景场为高温、高湿、垂直风速切变小的环境条件下,下沉气流的发展并非完全由蒸发、融化降温所产生的负浮力所支配,恰恰相反,降水拖曳力起主导作用;在不同的环境条件下,下沉气流发展的云物理过程可以有较大的差异。

英文摘要:

      The charcateristics of microburst were described, and the Doppler velocity field structure of a wet-type microburst occurring on July 22, 1997 in Beijingar eahas been researched. Using no nhydrostatic compressible meso-γ model, the main structure and evolution processes of this wet-type micro burst lines have been simulated, and the result of the simulation is very close to the measurement of the Doppler radar. The result shows that, under the environment of high temperature, high humidity, but with small vertical wind shear, the evolution of the dow ndraft is not fully supported by the negative buoy-ancy due to temperature decrease by evaporation and melting. On the contrary, precipitation trailing force play samain role in the procedure. This paper point sout that, in different environment conditions, cloud-physics for the evolution of the microburst may be very different.