Comparative Analysis of Three Covariates Methods in Thin-Plate Smoothing Splines for Interpolating Precipitation
Comparative Analysis of Three Covariates Methods in Thin-Plate Smoothing Splines for Interpolating Precipitation
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发表时间：
2012
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通讯作者：
Zheng-jia Liu
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作者：
Zheng-jia Liu
在薄板光滑样条插值中，利用2001 - 2009年中国728个气象站的逐日降水量资料，提取年降水量数据，分析了年降水量与DEM、海岸线到各点距离（DCL）两个协变量的空间相关关系，并对相关系数进行了分析。本文利用ANUSPLIN软件，分别以DEM、DCL和DEM-DCL为协变量，采用三种插值方法对降水量进行了空间插值，分析表明：（1）在全国尺度上，DEM插值法的平均绝对误差（MAE）为47.79，略低于DEM-DCL法的平均绝对误差（48.90），但明显低于DCL法的平均绝对误差（55.54），DEM法的MRE和RMSE也显著低于其他两种方法。(2)在区域尺度上，除西藏外，其他3种插值方法的误差与全国尺度的误差基本一致，其中DCL插值精度最高，DEM插值精度最差，说明DEM降水插值方法可广泛应用于全国尺度的相关研究，DCL插值方法在西藏地区值得推荐。
In the thin-plate smoothing splines interpolation,the accuracy of interpolation results is mainly determined by choosing the independent covariate.Annual precipitation data were extracted by using daily precipitation data of 728 meteorological stations from 2001 to 2009 in China.We evaluated spatial correlation relationships between annual precipitation and two covariates such as DEM and distance from the coastline to each point(DCL) and compared the accuracy difference of precipitation interpolation results from different covariates in the national scale and regional scale.All interpolation work has been conducted with the aid of the software of ANUSPLIN.We used three interpolation methods,which respectively considered DEM,DCL and DEM-DCL as the covariates to obtain spatial distribution of precipitation.Our analyses show that,(1) in the national scale,the mean absolute error(MAE) of interpolation method of DEM is 47.79,which is slightly lower than that of the method of DEM-DCL(48.90),while obviously lower than that of the method of DCL(55.54),and MRE and RMSE of the method of DEM were also lower than other two methods significantly.(2) In regional scale,the errors of three methods of interpolation are the same as that in national scale except Tibet.The accuracy of precipitation interpolation results was the highest using DCL method,and the poorest using DEM method.Results suggest that precipitation interpolation method of DEM could be widely used in some relevant national scale researches,and precipitation interpolation method of DCL was strongly recommended in Tibet.