Spatial interpolation of precipitation using the PER-Kriging method

Based on the parameter-elevation regressions on independent slopes model (PRISM),a PER-Kriging in-terpolation method is developed to consider the effect of elevations on precipitation interpolation.The method can comprehensively consider the complex relationships between grid points and observational sites in locations,horizontal distances and elevations.The method uses a reference elevation in precipitation interpolation in order to practise easily. The performance of the method is enhanced through nonlinear refitting of the elevation-precipitation relationship obtained by linear fitting scheme.Both PER-Kriging and Ordinary Kriging methods are tested on the Lancangjiang basin for precipitation interpolation and results are compared with each other.The result shows that PER-Kriging can effectively eliminate the errors introduced by the large geographic differences and the smoothing processes.Compared to Ordinary Krijing,the PER-Kriging method can reduce the mean error of interpolated precipitation by 20 mm,and the relative errors in different types of curve fitting are less than 12%.