Observational Evidence of the Influence of the Qinghai-Xizang (Tibet) Plateau on the Occurrence of Heavy Rain and Severe Convective Storms in China

Abstract

The advance and distribution of the belts of rainfall and heavy rainfall in China are closely related to sudden seasonal changes in the general circulation over East Asia. but the latter, to a great extent, may be the result of thermal and dynamic forcing by the Qinghai-Xizang (Tibet) Plateau. Observational evidence indicates that many synoptic systems have their origin in the planetary boundary layer over the plateau and its surroundings. They act as producers not only of severe weather events over the plateau itself, but also of very important rain-bearing synoptic systems over eastern, southern, and even northern China that have been steered out of the plateau. The present study is based on excessively heavy rainfall that have occurred during the past 50 years(1931?80), and which caused serious, damaging floods in much of China. The presence and influence of Tibetan weather systems could be found in most of these heavy rain-fall events. The low-level vortices originating in the plateau play a very significant role in producing the heavy rains.