中文摘要：

本文分析了降雨不均匀入渗补给的产生机理，应用地质统计学方法研究了次降雨入渗补给系数的空间变异性，建立了协方差函数与方向角的函数关系；对次降雨入渗补给系数进行了Karhunen-Loeve展开，通过求解特征值、特征函数及随机向量模拟次降雨入渗补给系数随机场。分析结果表明，在水平径流微弱、潜水面坡度小的地区，平稳场理论可以有效地描述次降雨入渗补给系数空间分布规律，KL展开法具有优越的收敛速度。

英文摘要：

The mechanism of rainfall infiltration is studied and the spatial variability of subrainfall infiltration coefficient is analyzed by geostatistical method. The paper establishs the equation between covariance function and directional angle of the random contribution of rainfall. By solving eigenvalues and eigenfunctions, Karhunen-Loeve expansion of subrainfall infihration coefficient is worked out with random vectors to simulate random field. It is shown that random field theory can depict the distribution law of subrainfall infiltration coefficient in level land with low horizontal flow and small slope of shallow water table. Karhunen-Loeve expansion can simulate the stochastic field efficiently because of its better convergence than other simulation methods.