Spatio-temporal Variations Analysis of Air Temperature and Precipitation in Qilian Mountainous Region Based on GIS

Based on the technology of ArcGIS,Kriging Interpolation Method and Surface Analyst,the monthly mean air temperature and precipitation data during 1960 through 2005 from 18 weather stations in Mt.Qilian region were analyzed.Their spatio-temporal variations are as follows: ①There was an obvious ascending trend of the air temperature in Mt.Qilian region from 1960 through 2005,with an increasing rate at about 0.5 ℃/10a;the ascending trend was the most obvious in the middle 1990's,and the increasing rate was more than 1 ℃/10a.②The change of air temperature in Mt.Qilian region kept well in phase with the change of air temperature in northwestern China.The distribution regimes of air temperature were same in summer and winter,but the temperature difference between north and south slope of the mountain was smaller in winter than that in summer.The monthly lapse rates of mean temperature differed seasonally,with low value in winter and high value in spring.③There was an ascending trend of precipitation in Mt.Qilian region from 1960 through 2005,and the precipitation distribution changed regionally and seasonally;precipitation reduced from south-east to north-west,and precipitation was less than 12 mm in winter and reached 230 mm in summer.