畦面微地形空间变异性分析

Analysis on spatial variability of micro-topography in border fields

基于大量畦田实测数据,利用半方差方法分析各类畦块的田面相对高程空间变异结构特征,评价畦块几何参数与田面相对高程空间变异特征参数间的相关性,提出采用球状模型描述田面相对高程空间变异函数和估算空间变异特征参数的方法.结果表明,畦块几何尺寸和田面相对高程测点间距是影响田面相对高程球状半方差函数变程的重要因素,田面相对高程标准偏差和田面相对高程测点间距则对该函数基台值和块金值产生明显作用和一定影响.对任意已知规格的畦块,可基于5～10m测点间距范围内获得的相对高程标准偏差值并参考本文提出的估算公式,得到利用球状理论半方差函数描述各类畦块田面相对高程空间变异特征的经验参数估值.

Based on a great amount of field survey data, the semi-variance methodology is applied to analyze the spatial variability characteristics of field surface relative elevation （SRE） in different type of border fields. The correlation between the field geometry parameters and spatial variability characteristics of SRE is evaluated, and the ability of the spherical model used to describe the variogram of SRE and the method used to estimate the parameters of the variogram are discussed. The results indicates that the geometry of basin field and the distance between the observation points of SRE are important factors affecting the range of semi-variogram of spherical fitted model of SRE, and the standard deviation of SRE plays an important role in determining the sill of semi-variogram. Besides, the distance between observation points of SRE has remarkable effect on the nugget of semi-variogram. For arbitrary given basin field, the parameters of semi-variogram fired through a spherical model can be estimated according to the standard deviation of SRE obtained from data based on the observation distance in the range of 5 - 10m. The corresponding empirical formula is suggested.