A global sensitivity analysis approach for marine biogeochemical modeling

This paper introduces the Sobol’ indices approach for global sensitivity analysis (SA), in the context of marine biogeochemistry. Such an approach is particularly well suited for ocean biogeochemical models, which make use of numerous parameters within large sets of differential equations with complex dependencies. This SA allows for a detailed study of the relative influence of a large number of input parameters on output quantities of interest to be chosen. It is able to distinguish between direct effects of these parameters and effects due to interaction between two or more parameters. Although demanding in terms of computation, such a tool is now becoming affordable, thanks to the development of distributed computing environments. An applicative example is presented with the MODECOGeL biogeochemical model, and illustrates the advantages of this approach over standard local SA. •A global sensitivity analysis is performed on a biogeochemical model.•This analysis, using full Monte Carlo procedure, is based on so-called Sobol’ indices.•Such an approach is now affordable even for models with numerous input parameters.•The analysis is very informative and highlights direct and interaction effects.