Analysis on Spatial Interpolation of Precipitation in Guanzhong-South Shaanxi Based on GIS

[Objective] To compare the effects of four spatial interpolation methods and analyze the temporal and spatial distribution of regional precipitation.[Method] With Guanzhong-South Shaanxi for example,according to 59 years' precipitation data of 72 meteorological observation stations,combining with GIS spatial interpolation technique and 30 m×30 m DEM from international scientific data sharing service platform,four interpolation methods(IDW,ordinary Kriging interpolation method,ordinary Cokriging interpolation method and radial basis function interpolation method) were adopted to do the spatial interpolation of average rainfall of 72 observatory stations in Guanzhong-South Shaanxi.Then the precipitation data of 10 stations were randomly selected to test the results of 4 interpolation methods so as to determine the optimal interpolation scheme and analyze the spatial distribution characteristic of precipitation.[Result] Ordinary Cokriging interpolation method was the best which took into account the terrain factors and could really reflect the rainfall spatial distribution characteristic of the study area.Ordinary Kriging was the second,IDW and RBF were the worst.Further study showed that precipitation distribution in the study area had apparent latitudes characteristics,and was greatly influenced by terrain and topography.[Conclusion] Ordinary Cokriging interpolation method taking into account the terrain factors was the best,which was suitable for the region.