摘要
通过对1973—1985年5—9月700 hPa上四川盆地东北部出现的低涡的分析,发现川东北涡是造成三峡地区区域性暴雨的重要影响系统之一,尤其是切变类川东北涡,有利于川东北涡生成的环境场是500 hPa上盆地东北部处于高压脊前西北气流和副高外围西南气流的交汇处,700 hPa盆地内有切变线通过。文中还对一次川东北涡暴雨过程进行了Q矢量分析,发现在川东北涡形成前12—24小时内盆地上空500 hPa维持—Q矢量辐合带,低涡发生在其生成前24小时内对流层中、低层Q矢量散度的辐合重叠区内,从而为预报低涡的生成、维持提供了有益的依据。
The vortex over northeast Sichuan Basin is one of the main heavy rain-producing systems over San Xia region, especially, the vortex with 700 hPa shear line. The analyses of 500 hPa height fields and 700 hPa wind fields with the vortex from May to September of 1973-1985, show the favorable situations for formation of the vortex are: (1) the ridge line of the subtropical High is in the vicinity of 25 ° N, and 500 hPa. northwest and southwest currents meet over the northeast of the Sichuan Basin. (2) 700 hPa shear line is also over the Sichuan Basin. After the Q-Vector fields of one case of heavy rain by the vortex were analysed, it is found that a convergent zone of 500 hPa Q-Vector existed over the Sichuan Basin in advance of 12-24 hours in which the vortex was generated, and when Q-Vector convergent areas of middle and lower troposphere were overlapped, a vortex would be formed in the overlap area during the period of 24 hours. It is a good clue for forecasting formation of the vortex.
出处
《高原气象》
CSCD
北大核心
1991年第1期70-77,共8页
Plateau Meteorology
关键词
川东
北涡
暴雨
环境场
Q矢量分析
Vortex over northeast Sichuan Basin
Q vector analysis
Q vector divergence
