青藏高原东部的纬向涡旋的形成及其对邻近地区天气气候的影响

THE FORMATION OF THE ZONAL VORTEX IN THE EASTERN QINGHAI-XIZANG PLATEAU AND ITS IMPACT ON THE WEATHER-CLIMATE IN THE SURROUNDING AREAS

初夏时期,由于青藏高原东部地面及其上层空气迅速加热,而四川盆地上空增热较慢,在同一高度上形成明显的东西向温差,在高原东部与四川盆地之间形成一个天气尺度的纬向涡旋。本文分析了这个涡旋生成的热力原因及脱体东移的天气学条件和对邻近地区天气气候的影响。指出纬向涡旋的生成不仅对高原东侧边界层内的天气系统有直接影响,而且它的重复出现是造成高原东部初夏多雨和四川盆地夏旱的重要原因。

In early summer, the ground surface of the easternQinghai-Xizang Plateau and the air above are heated quickly while thewarming process of the air over the Sichuan Basin is much slower.As aresult, a remarkable east-west temperature difference at the same level isformed and a synoptic-scale zonal vortex develops between the easternplateau and the basin. Investigation is made of the thermal reason for thevortox formation, the synoptic conditions of its eastward movement andits imapct on the weather-climate in the surrounding areas, revealingthat the ortex has a direct influence on the weather system in theboundary layer over the eastern plateau, and its frequent occurrence maybe one of the important factors responsible for the early summer excessiverainfall in the eastern plateau and the summer drought in the Sichuanbasin.