摘要
为分析地形与取样数对大尺度Kriging插值精度的关系，在舒城县的山区、丘陵、岗区、平原等4个不同地形单元采集土壤表层（0—20cm）样品611个，进行可变取样数条件下的土壤全氮空间分异插值精度比较。半变异函数分析表明，4个地形单元块金值与基台值比值的平均值〈25％，具有强烈的空间相关性。Kriging插值精度标准均方根误差检验值（NRMSE）在各地形单元内都随着采样密度的增大而不断降低，插值精度提高；各地形单元之间，在相同的采样密度下，Kriging插值精度大小顺序为平原〉岗区〉丘陵〉山区，随着地形复杂程度增加，Kriging插值精度降低。NRMSE检验值平均变化率分析表明，地形越复杂地区Kriging插值精度提高越快。地形条件和取样数是影响大尺度Kriging插值精度的重要因素。
A total of 611 soil samples were taken from top soil （0 - 20cm deep） for examining the concentration of soil total nitrogen in Shueheng County, Anhui Province. Our objectives were to analyze the variation in the precision of Kriging interpolation in different topographical units and number of samples. Semivariograms of geostatistics indicate that the total soil nitrogen had a relatively good spatial autocorrelation in the study area. With the increasing sampling densities, the Normalized Root Mean Square Error （NRMSE） decreased, and precision of Kriging interpolation increased. Under the same sampling density, the accuracy of Kriging interpolation in the mountain area, hilly land, mound area and plain area increased orderly, indicating that the accuracy decreased with the increase in complicated degree of the topography. An analysis of the value of average development of the NRMSE shows that the growth of precision of Kriging interpolation differed significantly among four topographical units, with the highest value in the mountain area and the lowest in the plain. It can be concluded that topography and sampling densities are important factors affecting the accuracy of Kriging interpolation in large land areas.
出处
《水文地质工程地质》
CAS
CSCD
北大核心
2008年第5期86-91,共6页
Hydrogeology & Engineering Geology
基金
国家自然科学基金项目(40673028)
安徽省高等学校自然科学基金项目(2006KJ023B)
关键词
克里格插值
插值精度
土壤全氮
地形
舒城县
Kriging
interpolation accuracy
total soil nitrogen
topography
Shucheng County
