Study on a concentration calculation method considering stochastic uncertainty

A concentration system is a stochastic system whose main sources of stochastic uncertainty are from uncertain input to the hydrological model such as hydro-meteorological data, model structure uncertainty and model parameters' uncertainty. Based on the Nash model with parameter n = 3, using stochastic differential equations theory, the stochastic uncertainty of a concentration system resulting from model input was studied. The results showed that not only the mean solution process of the discharge process but also the deviation degree of errors, could get through the concentration calculation method considering stochastic input. And then the probability distribution of discharge process could be obtained by using the variance of discharge at each moment, which could provide the degree of uncertainty of prediction to predict the risk of loss in flood control decision-making.