梅雨期长江流域两类气旋性扰动和暴雨

TWO KINDS OF CYCLONIC DISTURBANCES AND THEIR ACCOMPANIED HEAVY RAIN IN THE YANGTZE RIVER VALLEY DURING THE MEI-YU PERIOD

文章通过分析长江中游大暴雨和特大暴雨个例，研究了两类梅雨涡的产生、演变及与之联系的暴雨发展过程．一类是移到长江中游的典型酉南涡，其斜压结构出现在副热带暖环境中，是在这个系统本身发生、发展的动力－热力过程中产生的；另一类是串行于梅雨切变线上的小型正涡度扰动，其演变过程更复杂一些．文章结合这两次个例对作者过去的一些结果作了验证、充实和归纳．并论及复杂暴雨发展过程的一些预报难点．

A case of heavy rain(1989)and a case of extremely heavy rain(1982)in the middle reaches of Yangtze River are analysed,respectively.They were associated with two kinds of low vortexes during the met-yu period.The genesis and evolution of the two kinds of mei-yu vortexes and the accompanied torrential rain development processes are studied.One is the typical southwest vortex,it likes a weak baroclinic cyclone,but its baroclinic structure is generated in the dynamic-thermal process of its own genesis and development in the subtropical warm environment.Another is the small-size positive vorticity disturbance travelling through the mei-yu shear line,its evolution process is more complicated.According to the two cases,some previous results from the authors themselves are verified,substantiated and sumed up in this paper.And,some difficult points of the forecasting of complicated heavy rain development processes are discussed.