THE EXCHANGE OF MASS BETWEEN STRATOSPHERE AND TROPOSPHERE OVER THE TIBETAN PLATEAU AND ITS SURROUNDINGS IN 1998

n this paper,using NCEP dataset and the Wei's method,we calculate the exchange of mass across the thermal tropopause during 1998 over the Tibetan Plateau and its surroundings.The results indicate that:(1)There is strong air transport from troposphere to stratosphere in summer over the Tibetan Plateau and its surroundings.The air transport reaches the summit in midsummer with three large value centers among which the Bay of Bengal is the largest and the other two large centers lie in the east and northwest of the Tibetan Plateau,respectively.In May and October the cross-tropopause mass exchange reaches balance.In other months the mass transport is from stratosphere to troposphere.(2)As far as the cross-tropopause mass exchange from June to September in 1998 is concerned,the net mass transport is 13.7×1018 kg from troposphere to stratosphere,So the area from Tibetan Plateau to the Bay of Bengal is a channel through which air mass gets into stratosphere from troposphere.