Climatological Characteristics of Water Vapor Transport Over Upstream Area of Yangtze River

Climatological characteristics were investigated for large-scale water vapor transport over the upstream area of Yangtze River based on the vertically integrated water vapor flux from 1980 to 1997.It was 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 Bengal and the South China Sea;and in autumn the water vapor is from the West Pacific Ocean.The upstream area of Yangtze River is a moisture sink,under the yearly average condition,the daily water vapor income is(61.9)×10~5 kg/s.The region,as a transferring station on the water vapor 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 around the areas.The water transports from the Bay of Bengal and the pleatu,and the South China Sea and the West Pacific Ocean are respectively the important affecting factors in drought and flood years.