Improved Gulf Stream separation through Brinkman penalization

The advantage of a smooth representation of bathymetry in terrain-following σ -coordinate ocean models is compromised by the need to avoid numerical errors on steep slopes associated with pressure gradient discretization or spurious diapycnal diffusion. Geopotential z -coordinate models avoid these errors, but greatly underrepresent the interaction of flow with a topographic slope, especially when the bathymetry is underresolved. Hybrid …