Multi-method global sensitivity analyses – results for a rainfall-runoff model

A sensitivity study was carried out for the discharge of a small Austriancatchment using three global sensitivity methods implemented in a conceptualrainfall-runoff model: Sobol’s method, the Mutual Entropy and the RegionalSensitivity Analysis (RSA). Since RSA is a graphical method, the Kolmogorov-Smirnoff statistic was used for obtaining a quantitative measure of the sensitivities.It was observed that the parameter rankings as well as the temporal sensitivitydynamics agreed in general between the methods. However, the agreement wasbest between Sobol’s method and the Mutual Entropy. The graphical RSA method,gave some additional insights about the relationship of parameter values anddischarge levels, which were not supplied by the other two methods. Finally, theimplications these findings have for model calibration are discussed.