Investigating climate-induced changes in shelf – open ocean exchange in the Atlantic using global ocean downscaling

To address shortcomings of global climate models (CMIP6) and project the impacts of climate change in the Atlantic Ocean with focus on regional scales, we downscale globally a 4-member ensemble of future climate projections (2 emission scenarios and 2 global climate models) with a NEMO-ERSEM coupled hydrodynamic-ecosystem ocean model. In our global ocean downscaling of climate projections, the resolution for the ocean is increased to ¼ of a degree and the river runoffs are represented more realistically in an attempt to better resolve the shelf break and the exchange of water between the shelf break and the deep ocean, as well as the influence of this exchange on both large and regional scales. Here, using the projections from our global ocean downscaling we investigate the cross shelf-open ocean volume, heat and salt transports along the Atlantic Ocean margins and how they may change in the near future (up to year 2070). We also present preliminary analysis for the role of changes in the large-scale circulation patterns versus changes in the regional water content/properties (e.g., heat and salt) on driving changes in the shelf-open ocean exchange, with a particular interest in the North Atlantic western boundary region and the Gulf Stream.