Surface heat flux parameterization and the response of ocean general circulation models to high-latitude freshening

A global ocean general circulation model (OGCM) is forced using mixed boundary conditions (i.e., a restoring condition on the upper level temperature but using a fixed, specified surface salt flux). A freshwater flux anomaly is then applied over the western half of the sub-polar gyre in the northern North Atlantic. Responses range from a halocline catastrophe at short relaxation times (strong coupling) to a very modest perturbation at longer relaxation times (weaker coupling). An accurate parameterization is therefore required to properly model the evolution of the response. -from Authors