%AKatsman, C. [Department of Hydraulic Engineering Delft University of Technology, Civil Engineering and Geosciences, Environmental Fluid Mechanics Delft Netherlands]%AKatsman, C. [Department of Hydraulic Engineering, Delft University of Technology, Civil Engineering and Geosciences, Environmental Fluid Mechanics, Delft Netherlands]%ADrijfhout, S. [Royal Netherlands Meteorological Institute, De Bilt the Netherlands, Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Utrecht the Netherlands, National Oceanography Centre Southampton, University of Southampton, Southampton UK]%ADrijfhout, S. [Royal Netherlands Meteorological Institute De Bilt the Netherlands, Institute for Marine and Atmospheric Research Utrecht Utrecht University Utrecht the Netherlands, National Oceanography Centre Southampton University of Southampton Southampton UK]%ADijkstra, H. [Institute for Marine and Atmospheric Research Utrecht Utrecht University Utrecht the Netherlands]%ADijkstra, H. [Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Utrecht the Netherlands]%ASpall, M. [Woods Hole Oceanographic Institution Woods Hole MA USA]%ASpall, M. [Woods Hole Oceanographic Institution, Woods Hole MA USA]%BJournal Name: Journal of Geophysical Research: Oceans; Journal Volume: 123; Journal Issue: 5; Related Information: CHORUS Timestamp: 2023-09-06 02:45:07 %D2018%IDOI PREFIX: 10.1029 %JJournal Name: Journal of Geophysical Research: Oceans; Journal Volume: 123; Journal Issue: 5; Related Information: CHORUS Timestamp: 2023-09-06 02:45:07 %K %MOSTI ID: 10061654 %PMedium: X %TSinking of Dense North Atlantic Waters in a Global Ocean Model: Location and Controls %XAbstract

We investigate the characteristics of the sinking of dense waters in the North Atlantic Ocean that constitute the downwelling limb of the Atlantic Meridional Overturning Circulation (AMOC) as simulated by two global ocean models: an eddy‐permitting model at 1/4° resolution and its coarser 1° counterpart. In line with simple geostrophic considerations, it is shown that the sinking predominantly occurs in a narrow region close to the continental boundary in both model simulations. That is, the regions where convection is deepest do not coincide with regions where most dense waters sink. The amount of near‐boundary sinking that occurs varies regionally. For the 1/4° resolution model, these variations are in quantitative agreement with a relation based on geostrophy and a thermodynamic balance between buoyancy loss and alongshore advection of density, which links the amount of sinking to changes in density along the edge of the North Atlantic Ocean. In the 1° model, the amount and location of sinking appears not to be governed by this simple relation, possibly due to the large impact of overflows and nonnegligible cross‐shore density advection. If this poor representation of the processes governing the sinking of dense waters in the North Atlantic Ocean is a generic feature of such low‐resolution models, the response of the AMOC to changes in climate simulated by this type of models needs to be evaluated with care.

%0Journal Article