Sensitivity of ecosystem parameters to simulated satellite ocean color data using a coupled physical-biological model of the North Atlantic

A means of assimilating simulated satellite ocean color data with a coupled physical-biological model of the North Atlantic Ocean is implemented, allo wing the relative sensitivities of different biological parameters to those data to be investigated. The model consists of an eddy-permitting general circulation model derived from the WOCE Community Modeling Effort and a nit rogen-based, four-compartment NPZD marine ecosystem model. Many of the para meters in marine ecosystem models are poorly known and via assimilation, we hope to better constrain their values. The control parameters chosen for t he variational assimilation are the model parameters involved in parameteri zations of recycling as these are the most poorly known. Simulated observat ions are taken while following several floats seeded in varying dynamical b iogeochemical provinces of the North Atlantic model domain over a six-month period. Twin experimental results show that, for the given functional form s of growth, mortality and grazing, the following parameters can be success fully recovered from simulated satellite ocean color data: nitrate and detr ital recycling parameters in the trade wind domain, zooplankton parameters at higher latitudes (westerly wind and polar domains), and the phytoplankto n mortality rate in all regions. By simultaneously assimilating ocean color data in different biological provinces, it becomes possible to successfull y constrain all ecosystem parameters at once.