Research on Precipitation,Precipitable Water and the Precipitation Conversion Efficiency of Altay Prefecture

Based on water vapor pressure data,4 times a day,and daily precipitation data from 1961 to 2007 recorded at 7 weather stations in Altay Prefecture,the precipitation characteristics are analyzed.The analyses show that the annual mean precipitation is increasing in Altay Prefecture,especially in summer and winter.However,in spring and autumn the increase is slowly.Spatially,the annual mean precipitation is increasing and from south to north,and decreasing from west to east.The precipitable water has decreased slightly since 2000.The precipitable water and the precipitation conversion efficiency are calculated and analyzed with empirical formula about atmospheric precipitation water.It is found that there is more precipitable water in summer than in winter in the prefecture.Spatially,the precipitable water increases from the periphery to the centre of mountains.The more precipitation area is corresponding with the less precipitable water area. The spatial and temporal distribution of precipitation conversion efficiency is increasing in the recent 47 a,and it is higher in winter.This indicates that there is more potential in exploring atmospheric water resources.