Abstract : 1C.28
Features of the water vapor transport and precipitation variation of the Tibetan Plateau and its surroundings

Changyan Zhou, Yueqing Li, Jun Peng
Institute of Plateau Meteorology, Chengdu, CMA

Climatological features are investigated for large-scale water vapor transport over the Tibetan Plateau and its surroundings based on the vertically integrated water vapor flux from 1980 to 1997.It is found that in winter and spring, the moisture of the region is mainly from the middle-latitude westerly water transport; in summer (July), the moisture comes from the Bay of Bengle and the South China Sea, and in autumn the water vapor is from the west Pacific Ocean.

The abnormal progression and retreat of the moisture with southlies will affect the occurrence of floods and droughts. Sichuan and Chongqing Basin, as a transferring station on the water transport way from the South China Sea and the west Pacific Ocean to Northwest and North china in summer and autumn, plays a great role on the water budget of the areas around.

The precipitation of Sichuan and Chongqing Basin had been decreased from the year of 1951 to 2000 and the decrease trend is the most obvious between 1990 and 1997. There is a evident difference of precipitation in the eastern and western part of Sichuan and Chongqing Basin. The precipitation in the western part had been decreased in 50 years, and contrary to the western part , the precipitation in the eastern part showed a increased tendency. The weakeness of northward and westward march of the water vapor transport with summer moonsoon has a important influence on the variationofprecipitation in the region.