Assessing Uncertainty in Hydrological Processes Using a Fuzzy Vertex Simulation Method

Abstract

AbstractIn this study, a fuzzy vertex simulation method (FVSM) is developed for assessing parameter uncertainty on modeling outputs of Xiangxi River Basin in China. The FVSM couples a fuzzy vertex analysis approach with a semidistributed hydrological model to reflect effects of uncertain parameters on hydrological possesses. In FVSM, the topography-based hydrological model (TOPMODEL) is used for predicting streamflow of saturated area in the catchment by tackling the distribution of the topographic index; the fuzzy vertex analysis method specializes in dealing with ambiguous coefficients based on fuzzy sets theory and α-cut analysis technique. The modeling outputs (i.e., Nash-Sutcliffe efficiency coefficient and the sum of the squared errors) indicate a good performance of TOPMODEL in describing the daily streamflow at four hydrological stations in the study basin. The uncertainties of two parameters (M and T0) are examined under different α-cut levels. The results indicate that flow interval is wide unde...