Pratik P. Aghor, Matthew McKinley, Annalisa Bracco
Abstract This work investigates through a modeling exercise the interaction of a strong, surface current with isolated seamounts, focusing on the Gulf Stream and Atlantis II, one of the New England Seamounts. The roles of bathymetric details and model resolution are investigated with three simulations that consider realistic realizations of the seamounts but different resolutions (NESM runs at 1 and 5 km horizontal resolution) or a quasi‐idealized Gaussian rendering of the bathymetry that includes three seamounts (SM3 simulation) at 1 km resolution. The SM3 run captures a broad range of physical phenomena modeled by the NESM runs. By quantifying the energetics near the bottom, we show that vertically coherent eddies are generated through the interaction with the topography. On the anticyclonic side of the seamounts, an overturning centrifugal instability due to negative Ertel potential vorticity (PV) in the bottom boundary layer is identified. A combination of internal wave activity and centrifugal instability enhances vertical mixing near isolated seamounts, with a model representation that strongly depends on both resolution and topographic complexity. The annual mean diapycnal mixing coefficient is approximately twice as large in the most realistic case with respect to the lower resolution or idealized bathymetry configurations.