环境流场对台风发生发展的影响

本文用简单的数学模式、基于CISK理论,从动力学角度分别讨论了在对流层低层气旋性切变基本气流作用下以及对流层上层切变基本气流作用下,台风低压增长率的改变。结果表明,对流层低层的气旋性切变基本气流可以使增长率明显增大,这从动力学角度解释了赤道西风或西南季风的加强以及适中强度的冷空气影响有利于台风生成和发展的天气事实。对流层上层反气旋性切变基本气流有利于台风发展,而对流层上层气旋性切变基本气流使台风削弱。但对流层上层环境流场的影响相对比较微弱。

THE EFFECT OF AMBIENT FLOW ON GENERATION ANE DEVELOPMENT OF TYPHOON

In this paper, the shearing basic flow is introduced into the CISK theory developed by Charney and Eliassen (1964).Then, the growth rate of typhoon depression is investigated with a simple numerical model under the effect of cyclonic shearing basic flow in lower troposphere and the effect of shearing basic flow in upper troposphere. The cyclonic shearing basic flow in lower troposphere increases the growth rate. It is explained with dynamic point of view that the enhancement of equatorial westerly or southwest monsoon and the influnce of cold front with moderate strength are conducive to generation and development of Typhoon. The effect of anticyclonic shearing basic flow in upper troposphere is condu- cible for development of Typhoon. But, the cyclonic shearing basic flow in upper troposphere will depress Typhoon. The effects of ambient flow in upper troposphere are wean on development of Typhoon.