Spatialtemporal Distribution of Precipitation in the Aksu River Basin,Xinjiang

Based on the physiogeographic features in the Aksu River Basin,in this paper the precipitation data observed by 11 meteorological stations in the drainage basin and its vicinities are used to analyze the spatial and temporal change of precipitation in the drainage basin during the period of 1960-2003.The results show that precipitation in the drainage basin has been in an insignificant increase trend since 1960,the liner trend rate is 0.522,and the precipitation has increased in an extent of 13.21 mm/10 a since the 1970s.The interannual change of precipitation is significant and comparatively unstable,and the average coefficient of precipitation change(Cv) is 0.38.Based on DEM data and by using GIDS method as the interpolation formula,it is derived that there is a latitudinal distribution of annual precipitation,and the precipitation is closely related to landforms.The result of regression analysis reveals that there is a quadratic correlation between precipitation and elevation,and the correlation passes the significance test of 0.001.Precipitation increases significantly in a zone over 2 000 m a.s.l.,and the precipitation on windward slope is higher than that on leeward slope.Analyzed from the change of Cv,it is found that the spatial difference of precipitation is not so significant and in a decrease trend since recent 44 years.