High-Resolution North Atlantic Ocean Modeling: Impact of bathymetry, tides, and atmospheric forcing

In Chassignet and Xu (2017), the authors argued that the next threshold for a significant improvement in western boundary currents representation (i.e., the Gulf Stream in the North Atlantic) is an increase in the horizontal resolution from an eddying 1/10° to a submesoscale enabled 1/50° grid spacing. They showed that, as the resolution is increased to 1/50° (~ 1.5 km at mid-latitudes) from 1/12°, the representation of Gulf Stream penetration and associated recirculating gyres shifts from unrealistic to realistic and that the penetration of eddy kinetic energy into the deep ocean is drastically different and closely resembles observations. They however noted several discrepancies between the high-resolution 1/50° numerical simulation and observations. The first one was no variability in the sea surface height spectra wavenumber spectral slope between high/mid-latitudes and the equator. The second one was an area of high sea surface height variability and surface EKE wider than observed near the New England seamount chain which suggests that interactions with the topography may be overemphasized in this model configuration. We will show that the inclusion of high-resolution bathymetry, tides , and atmospheric feedback significantly improve the model's abilities to represent the observed ocean variability and Gulf Stream pathway.