Uncertainty analysis of parameters for simulating river flow using GLUE method for a coupled land surface- hydrology model

In recent years, the determination of the uncertainty of hydrological models in the hydrological research has been very much taken into consideration. Although the parameters of the hydrological model are usually determined by calibration, but there is considerable uncertainty in the model parameters. In this study, with the aim of calibration and uncertainty analysis of coupled model ALSIS-HBV, GLUE method has been used in the Karkheh basin. Determining the main source of uncertainty and identification of parameters, as well as estimating uncertainty in the results of river flow simulation are other goals of this research. The findings show that K2, Fcap, MaxBas, lp, B, degw and ttlim parameters are main sources of river flow uncertainty, and the parameters K2, Fcap, B, lp and perc are the most identifiable parameters. In general, the model's performance evaluation for river flow simulation in karkheh basin, especially in calibration period is good and acceptable, and most river flow observations are in 95% confidence intervals, Therefore, the probability distribution calculated from the river flow can be used to predict the flow of the river.