Mehdi Fuladipanah1 and Mehdi Jorabloo
Abstract
Sensitivity analysis as a technique is applied to determine influential input factors on model output. Variance-based sensitivity analysis method has more application compared to other methods because of including linear and non-linear models. In this paper, Snowmelt Runoff Modeling (SRM) which has more application to simulate snowmelt-runoff flow in mountainous catchments, has been considered. SRM has ten input factors as: Q (Daily discharge), Cs (snowmelt Runoff Coefficient), CR(Rain runoff Coefficient), a (Degree-Day Factor), T (Number of Degree-Days) , ?T (Temperature Lapse Rate), S (Snow Covered Area), P (Precipitation), A (Area), k (Recession coefficient). These factors importance was determined using the first order of Fourier Amplitude Sensitivity Test. Sensitivity index was applied to evaluate importance of factors. More value of this index is indicating more important factor. Results show that A, CR, P and k are more influential factors with sensitivity index: 0.1491, 0.1475, 0.1042, 0.1037, respectively. These factors are including 86.93% of total output variance.