Comparison of modeled and observed turbulence (lower 2 panels) indicates that, although the model does include surface-forced turbulence and bottom boundary layer turbulence, its structure is quite different from observed surface layer and bottom turbulence. Perhaps even more importantly, the model is devoid of turbulence in the interior.
Since models do not explicitly (and usually not implicitly either) include an internal gravity wave field they can never properly reproduce the low Richardson number condition for turbulence. More appropriate parameterizations that include an internal gravity wave field must be explored.
The lower panel shows the overlap of low Ri with high turbulence.
Enhanced turbulence due to the superposition of internal gravity wave shear on the coastal upwelling jet, J. Geophys. Res., 112, C06024, doi:10.1029/2006JC003831, 2007 (G. Avicola, J.N. Moum, A. Perlin and M.D. Levine) [pdf]