Influences of Westerly Wind Interannual Change on Water Vapor Transport over Northwest China Summer

Abstract

The zonal index and the divergence of summer water vapor transport flux over Northwest China are analysed by using NCEP/NCAR monthly mean reanalysis data from 1970 to 1997. The analysed results show that the interannual change of moisture flux divergence resulted by moisture advection is constant, but resulted by wind field convergence or divergence is unstable. The wind field convergence is stronger in strong west wind years. So we can conclude that the interannual changes of summer water vapor over Northwest China is mainly resulted by wind field convergence or divergence.