黄土高原降雨量空间插值精度比较——KRIGING与TPS法

Precise comparison of spatial interpolation for precipitation using KRIGING and TPS(Thin plate smoothing spline) methods in Loess Plateau

黄土高原地域广阔,降雨量时空分布复杂多变,插值方法将影响降雨量的时空变化特征分析,进而影响水文及土壤侵蚀模拟效果。采用黄土高原河龙区间及毗邻地区50余个气象站点20年(1981—2000年)的降雨量数据,分别利用KR IG ING(克里金)和TPS(薄板光滑样条)方法对多年平均、年和月降雨量进行插值,对研究区内27个站点进行交叉验证,比较和分析其插值精度变化特征。结果表明:1)无论多年平均,还是年和月尺度,KR IG ING与TPS方法降雨量插值结果都能正确反映河龙区间降雨量的空间变化趋势,2种方法交叉验证平均一致性指标(A)绝对值相差均在±0.01范围内,2种方法面平均插值精度均没有显著性差异。2)不同时间尺度的插值精度,KR IG ING与TPS 2种插值方法的交叉验证平均一致性指标(A)均表现出多年均值优于4月约14%,优于年值约19%,优于7月约35%。

Loess Plateau covers large area in China,where precipitation shows complicated spatiotemporal variability.The interpolation method is an integral component for analyzing the spatial and temporal characteristics of precipitation in Loess Plateau,as well as they are crucial conditions for obtaining reliable results of hydrological and erosion modeling.In this paper,the precise of KRIGING and TPS（Thin plate smoothing spline） methods,were compared and analyzed according to the observed data including average annual rainfall,yearly and monthly rainfall for 20 years from 1981 to 2000 from 50 meteorological stations in the He-Long Section and the nearby regions.The performance of the two different algorithms,KRIGING and TPS,were verified and compared by cross-validation test based on the data of 27 stations.The results indicated that： 1） For the interpolation of the average annual precipitation,yearly and monthly precipitation,both the KRIGING and TPS methods can reflect the spatial distribution of precipitation in the He-Long Section.The absolute value difference of average A（the index of agreement） for whole period for both of the methods are less than ±0.01.There is no significant difference for the precipitation interpolation precision between the KRIGING and TPS methods.2） The differences of the interpolation precision for both of the methods at different time scales show nearly the same trend.The average A for the average annual precipitation is better than that of April about 14%,better than that of the annual precipitation and the July about 19%,35% respectively.