A comparison of sensitivity analysis methods and their value for comparing denitrification models

Numerous methods exist to gain insight on a model performance. Sensitivity analysis (SA) tools provide information on how a model output depends on model parameters. It is widely argued that SA is an essential tool for assessing model uncertainty. Here, I review global SA using Variogram Analysis of Response Surfaces (VARS), variance-based methods (Sobol' indices) and polynomial chaos expansion. For the comparison, we use a set of denitrification models, which are needed to assess the fate of nitrate, a global challenge. For each of the models, we assess the uncertainty and reliability of predictions, and the use of SA tools in designing experiments to reduce model uncertainty.