暴雨系统中环境涡度场与散度场之间相互关系

THE RELATIONSHIP BETWEEN ENVIRONMENTAL VORTICITY AND DIVERGENCE FIELD ASSOCIETED WITH HEAVY RAIN SYSTEMS

摘要: 观测事实和理论研究表明,暴雨系统的形成和发展与环境涡度和散度的分布和演变有十分密切的关系.因此用涡度方程和散度方程来诊断和分析流场结构比其它方程(如动量方程)更为直接,物理意义也更加清楚,这就吸引气象学者把它用于分析实践.如Matsumoto1等用完全涡度方程和散度方程各项来诊断中尺度系统发展过程中对流活动的作用;Schaefer2选取散度方程中与发展有关的项来诊断未来风暴的发生,发现其相关率可达90%以上.我国学者3,4也研究过散度方程各项的大小以及某些重要项对暴雨形成的作用.

Abstract: This paper presents the time-area averaged profiles of each term in vorticity and divergence equations over heavy rain region during 19-21 June 1982 and discusses the relationship and changing features between vorticity and divergence field.It has been verified that the ageostropic motion and nonlinear structures of wind field are closely related to the changes of the divergence field.