摘要
1983年7月末发生在川陕地区的大暴雨,造成陕南特大洪灾.大、中尺度天气分析指出:造成这次暴雨过程的直接中尺度系统是受控于稳定天气尺度系统的高原东侧西南涡和中-α尺度切变线;SW 涡初生于高原东侧西风气流汇合处、印度西南季风左半侧;西南季风活跃、副高东阻及中高纬冷空气的入侵形成了西南涡区斜压性质的对流不稳定;“东高西低”环流形势是低涡切变线生成、发展的有利条件,这反映了高原地形及系统异常的动力作用.诊断分析表明:SW涡是生成并发展于700hpa 的浅薄系统,具有暧湿中心结构.
During the period of 26-31 July 1983,a heavy rainfall event occurredover some parts of Sichuan and Shaanxi,resulting in a severe flood ca-tastrophe in the southern Shaanxi.The large scale and mesoscale synopticalanalysis indicated that the mesoscale systems,which directly inducedthe heavy rainfall event,were the plateau-east-side southweast(SW)-vortex and a meso-a scale shear line that were controlled by the stablesynoptic scale systems.The SW-vortex was generated over the east edgeof Yun-Gui Plateau,where there was west flow convergence,in the leftside of southwesterly Idian monsoon current.It reduced baroclinity conv-ective instability that southwesterly monsoon flow being active,subtrop-ical high blocking in the east and the cold air invading from mid andhigh latitudes.It was found that the“east high and west low”circulationPattern was favorable for the generation and evolution of both the SW-vortex and shear-line.It showed the dynamical mechanism of plateauconfiguration and system variance.Diagnostic analysis indicated that theSW-vortex was a shallow mesoscale system that was generated and evolvedat 700hpa,with a warm moist center.
出处
《兰州大学学报（自然科学版）》
CAS
CSCD
北大核心
1992年第2期163-168,共6页
Journal of Lanzhou University(Natural Sciences)
关键词
切变线
天气分析
诊断分析
SW涡
shear line
weather analysis
diagnostic
analysis
SW-vortex
southwestern monsoon flow
