Near-term Ocean Dynamics and Biogeochemical Interactions in the North-Baltic Sea System: A Model Validation

Both the North Sea and the Baltic Sea experience similar problems such as pollution and eutrophication, even though they do not share the same ocean dynamics, hydrology and biogeochemistry. Because both seas are highly vulnerable to anthropogenic pressure and climate change, several international programs have been established to monitor and mitigate nutrient supplies to the entire region in order to reduce eutrophication risks. An important, but poorly studied area is the Skagerrak-Kattegat transition zone, where complex water masses and nutrient exchanges between both seas occur. To better understand these exchanges we use an ocean model for the North and Baltic Seas (NEMO-Nordic) that includes this transition zone and is coupled to the Swedish Coastal and Ocean Biogeochemical (SCOBI) model. With the model, we asses inter-annual and multidecadal variations in the entire North Sea and Baltic Sea system specifically looking into the Skagerrak-Kattegat dynamics. Here, we address the validity of the model by comparing our results to an extensive observational data set and present preliminary results. We focus on the model performance for the Skagerrak-Kattegat transition zone and analyze if the model can be used as a basis for further model development and projections.