采用非参数假设检验方法,对年产沙模数估计方程中下垫面因素的时变影响作定性分析,结果表明,对于一般流域,如果没有人类活动或自然灾害破坏导致下垫面条件的突变,下垫面因素对产沙的影响可看作是时不变的.

In modelling of sediment yields,the effects of time-variation of geomorphotgic and geologic factors on soil erosion were generally neglected. Errors of this neglection affect-ed the sediment yield models obviously. In this paper,a revised universal soil erosion e-quation was selected, the effects of errors of this neglection on it were tested by non-parametric hypothetical test method of Kolmogorov-Smirnov for a 22-year period within 21 catchments of the middle Huanghe River region,and the results show that the effects of errrors of this neglection on soil erosion were not significant,at 5% probability level.