Because of the spatial-temporal variability and inhomogeneity of natural factors and the uncertainty of human activities, runoff and sediment yielding is a complicated nonlinear process.
由于自然因素的时空变异性和不均一性以及人类活动的不确定性，因此产流产沙是一个复杂的非线性过程。
2
The spatial variability of runoff area has a great effect on the time-space input of sediment supply into rivers.