非饱和水分运动参数空间变异与最优估值研究

Study on Spaital Variability and Optimal Estimation of Unsaturated Flow Parameters

以野外砂壤土３０ｍ×３０ｍ空间的实测土壤参数试验为基础，通过对实测数据的统计分析得到饱和水力传导度ＫＳ及容水度Ｃ遵从正态分布，而孔隙大小分布参数α遵从对数正态分布。应用变差函数对参数ＫＳ和α的空间结构进行分析得到两参数的空间结构可用球状变差函数模型进行描述。根据Ｋｒｉｇｉｎｇ最优估值理论，分别对两参数空间的值进行了估计，结果表明本研究的野外实测试验点的数目减少２６％即可满足精度要求，同时与克立格方法相比采用协克立格方法对参数ｌｎα进行估计，其估计方差平均减少６．８７％。

The data for soil hydraulic properties collected on a 30m×30m field with sandy loam soil has been investigated by the statistical method,the results show that the saturated hydraulic conductivity K S and soil water capacity are the normally distributed,and the pore size distribution parameter α is the log normally distributed respectively.According to geostatistical method,the spatial stuctures of K S and ln α are characterized by the spherical semivariogram model.The Kriging technique is used for the spatial estimation of K S and ln α ,the results indicate that the estimating variances are approximately the same as those when the sample points are reduced by 26 percent,and the average estimating variance of Cokriging method is about 6 87 percent lower than that of the Kriging method for parameter ln α .