Cross-sections of sigma-0 along 33W to a depth of 500m for summer (top) and to 3000m for winter (bottom). The thick line is the mixed layer base. HYCOM was run with KPP mixing and relaxation boundary conditions to produce the “best” possible simulation. Nearsurface fields are qualitatively similar, although differences in detail exist. At middle depths, water with lower density penetrates deeper in in the simulated fields than in observations.