气旋快速发展的机制分析

MECHANISM ANALYSIS OF RAPIDLY DEVELOPING CYCLONE

本文主要分析爆发性气旋的形成机制。通过对一个爆发性气旋生成的个例分析表明，高空急流核的东传及高空强风动量的下传加强了低层强风带及气旋性涡度切变；涡度及位涡垂直分布显示，以对流层中高层的强涡度为背景，气旋在中低层得以爆发性发展，使得强盛期的气旋发展成为一个上下一致的垂直涡度柱；低空强风带的加强一方面由于高空急流的动力强迫作用，另一方面来源于低纬空气质点对强风动量的输送作用。另外，本文还利用拉格朗日方法进行空气质点的轨迹积分，以分析高空纬向气流及低层强风带的变化及输送作用。

This paper ana1yses the forming mechanism of explosive cyclone. An exampleanalysis of forming explosive cyclone shows:east propagation of upper jet flow nucleus anddownward propagation of large momentum of upper air strengthen severe wind belt and cy-clone vorticity shear of low layer. Under the background of strong vorticity of high and mid-dle layer,cyclone of middle and low layer develops rapidly,enabling the cyc1one being a verti-cal vorticity pillar.The reason of the strengthening of severe wind belt of low layer is due to the dynamicforce effect of upper layer jet and the transport effect of air particle of low latitude.The trajectory integration of air particle is done with a Lagrangian method,in order toanalyse vari&tion of latitude air flow of upper layer and transport effect of strong wind betl oflow layer.