Séminaire
Adiabatic theories of ocean circulation and density structure have a long tradition - from the concept of the ventilated thermocline to the notion that deep ocean ventilation is controlled by westerly winds over the Southern Ocean.
In this study we explore these ideas using a recently developed Lagrangian ocean model (LOM), which simulates ocean motions by computing trajectories of water parcels. A unique feature of the LOM is its capacity to model ocean circulations in the adiabatic limit, in which water parcels exactly conserve their densities when they are not in contact with the ocean surface. We take advantage of this property of the LOM and consider the circulation and density structure that develop in an ocean with a fully adiabatic interior (with both isopycnal and diapycnal diffusivities set to zero).
Despite the idealized bathymetry, the relatively course model resolution, and the lack of atmospheric coupling, the non-diffusive ocean maintains a density structure, meridional overturning and heat transport that are broadly in line with those observed in the Atlantic Ocean.
We conclude that the adiabatic limit for the ocean interior provides the leading-order solution for ocean overturning and density structure, with tracer diffusion contributing first-order perturbations.