Uncertainty and observability of target ecosystem indicators within the operational system for the North-West European Shelf

We developed biogeochemical ensembles within the research and development (R&D) version of the coupled physical-biogeochemical operational system on the North-West European Shelf (NWES). Based on the ensembles we analyse the uncertainty of a selected set of target ecosystem indicators, such as the net primary production, phytoplankton phenology and community structure, near-sea-bottom oxygen, particulate organic carbon (POC) fluxes, trophic efficiency and pH. By performing data assimilation experiments with a newly developed ensemble-3DVar system we determine how observable are these target indicators with the standard set of observations for the surface total chlorophyll derived from the ocean color satellite data. Some conclusions for how to improve the target indicator observability are being discussed.