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The project builds on recent technological developments to push the boundary of Lagrangian observation networks toward the Antarctic slope and shelf. In addition, by combining these new observations with existing datasets (including seals, Argo, and ship-based datasets) and state of the art numerical model, it aims at providing an original synthesis of the large-scale dynamics of the Weddell Sea.
The 5-year WAPITI project funded by the European Research Council will investigate a range of different aspects of the Weddell Sea circulation, using a combination of targeted observation, existing observation database, and high-resolution models, as well as the use of new, specifically developed autonomous instruments. The ultimate goal of the project is to refine our understanding of the water-mass transformation and pathways in this key region of the world’s ocean.
Existing observation databases will be used to revisit descriptions of the surface layer dynamics, as seen under sea-ice. Using this dataset, the question of the subpolar gyre intensity and variability will also be tackled.
Water from the subpolar gyre can be partly injected onto the Antarctic continental shelf and will eventually flow under the ice-shelf to form bottom water. The dynamics of the transfers across the intense slope current will be approached using a specifically designed high-resolution numerical model of the region.
Once water-mass enters the continental shelf, it undergoes large transformation before it is injected under the ice shelves. A network of drifting Lagrangian floats and moorings will be measuring water-mass properties under sea-ice year-round.
The turbulence and water-mass changes associated with bottom water overflow will be investigated using specifically designed floats, which will drift in the bottom boundary layer, measuring water-mass characteristics and the vertical profile of currents along their path.