“98.7.21”武汉特大暴雨大气环流特征分析

Case Study of Circulation Characters for an Extremely Heavy Rain in Wuhan

对“98 .7.2 1”武汉特大暴雨发生时大气不同尺度的环流的特征进行了分析研究 ,指出亚欧中高纬度经向环流的持续发展、西太平洋副热带高压持续的异常偏南及其内部强度变化的不均、中层短波槽系统的东移阻滞和与暴雨相伴而生的β中尺度强涡旋系统 ,是这次暴雨过程大气环流的典型特征。还对直接造成武汉特大暴雨的强对流云团、β中尺度强涡旋系统的部分动力和热力结构进行了分析。

This paper analyzes different scales atmospheric circulation characters during the extremely heavy rain occurred in July 21,1998 in Wuhan, and points out that the lasting development of meridional circulation in middle and high latitude Europe Asia area, abnormally enduring south of west Pacific subtropical high and its non uniform changes,the eastward moving of short wave's damming at middle level and the strong meso β scale vortex system accompanying the torrent rain are the typical characters of atmospheric circulation in this heavy rain event. The dynamic and thermodynamic structure of the convective clouds and the strong vortexes, which resulted directly in the heavy rain, are also analyzed in the paper.