暖湿气流中大暴雨成因的中尺度数值试验

NUMERICAL SIMULATION OF HEAVY RAIN IN A MOIST ATMOSPHERE

摘要: 近年来的研究表明,暴雨的成因是复杂多样的。国外发现了六种与锋面相联的雨带,其中有暖区雨带。国内,在华南、华东甚至内蒙均发现了暖区暴雨。从天气学分析得知,这些暖区暴雨不同于一般的锋面降水,它与冷空气没有联系,用一般的锋面抬升及位势不稳定理论无法解释这类暴雨。它的发生是与暖湿气流内部的不稳定有关,如对称不稳定、重力惯性波不稳定等均能造成暖区内的大暴雨。

Abstract: A detailed analysis is made with a three-dimensional numerical simulation for the evolution of a heavy rain in a moist atmosphere on 12-13 June,1984.It is found that the increase of wind vertical shear may stir up a kind of internal gravity waves with approximate speeds of 23.1 m/s and wavelength of 500-600 km.The waves are a mechanism of triggering the heavy rain in the warm,moist atmosphere.