Labrador Sea is a climatically critical region where the formation of dense water masses influences the strength of the Atlantic Meridional Overturning Circulation (AMOC). Winter mixed-layer depth and water mass transformation in this region are governed by the interplay of atmospheric cooling, advection by boundary currents, exchange via mesoscale eddies, sea-ice processes, precipitation, and freshwater input from the Greenland margin and upstream sources. However, quantifying the relative contributions of these processes remains challenging, as freshwater anomalies often concentrate near steep topography and narrow boundary currents—features that coarse-resolution products struggle to resolve effectively. Furthermore, under future global warming scenarios, increasing freshwater input from melting ice in the Arctic and adjacent waters suggests a potential freshening of the inflow to the Labrador Sea. To address this, the present study employs a regional MITgcm model of the Labrador Sea with 3.5-km resolution. The study aims to investigate how enhanced freshwater forcing modulates upper-ocean stratification, kinetic energy distribution, and wintertime deep convection in the region, thereby influencing the strength of the overturning circulation. The model uses KPP vertical mixing, dynamic-thermodynamic sea ice, realistic bathymetry, open-boundary conditions from GLORYS, and hourly ERA5 atmospheric forcing. In addition to incorporating runoff from West Greenland, the model focuses on the freshening of inflowing surface waters to examine how coastal freshwater is redistributed via boundary current systems and the efficiency of its exchange with the interior of the actively convective region. This work contributes to understanding how regional freshwater pathways and boundary-current dynamics regulate Labrador Sea water-mass transformation, with implications for subpolar North Atlantic variability and overturning circulation predictability.
 

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