The role of local models and data sets in the Joint Global Ocean Flux Study

The purpose of local studies within the Joint Global Ocean Flux Study (JGOFS) is to determine something, typically a model with parameter values, that is useful for making regional or global estimates of fluxes. An iterative process of improvement should lead towards a model that fits available local data well, and local data that constrain the range of possible models well, so that the extrapolation from local to global can be made with confidence. This paper addresses issues in evaluating the fit of models and the constraining power of data. For illustrative purposes it treats the data and the form of the model as fixed, so that improvement is confined to the parameter values of the model. The plankton model of Fasham et al.(1990) (Journal of Marine Research, 48, 591–639) fits the data of the JGOFS North Atlantic Bloom Experiment of 1989 reasonably well, and that data set constrains the parameters of that model reasonably well. Studying their interplay suggests directions for improvement in both.