Parameterization of the oceanic mixed layer use in general circulation models

Graduation date: 1978The behavior of different parameterizations of mixed layer physics\ud when used in an oceanic general circulation model (OGCM) having coarse\ud resolution of the upper ocean is examined. The method of parameterization\ud is expected to have an important effect on the resulting sea surface\ud temperature, and hence affect the model's overall fidelity from the viewpoint\ud of air-sea interaction. Tests of three possible parameterizations\ud differ in the manner in which the mixed layer depth is determined: predetermination,\ud diagnostic determination, or prognostic determination.\ud The sea surface temperature is taken to be equivalent to the top OGCM\ud layer temperature in the first two methods, while it is found prognostically\ud in the third method. Results show that for typical forcing cases\ud such as strong insolation, weak surface cooling or weak winds, mixing is\ud insufficient to cause heat transfer between the top two OGCM layers,\ud which occupy the uppermost 500 m of the model. The predetermined and\ud diagnostically determined mixed layer depth parameterizations reduce to\ud a diffusive mixing parameterization, while the prognostic approach satisfactorily\ud models mixed layer depths for all forcing cases. The prognostic\ud method also agrees most closely with the results of a mixed layer\ud model and with observations