Regional Features and Variations of Water Vapor in Northwest China

Abstract

Analyzing the regional features and variations of water vapor in Northwest China reveals that: There are three climate regions in Northwest China,i.e.,region of westerly belt,region of plateau and region of East Asian monsoon.Water vapor is transported from Northwest and West and Southwest to Northwest China.The atmosphere precipitable water and vapor flux in Northwest China is abundant in the region of East Asian monsoon,followed by the region of westerly belt,and then the region of plateau.In the vapor flux field there is a convergence center of precipitation.The net vapor flux was negative in the region of westerly belt before 1978,and then turns to positive.The net vapor flux was negative in the region of plateau during the past 43 years.Before the 1990s,the net vapor flux was positive in the region of East Asian monsoon,and then turns to an equilibrium state,with a value higher than the other two regions.There were abrupt changes of precipitation and water vapor in the region of westerly belt in 1990 and 1985,and no in the other two regions.