Density coordinate mixed layer models

The development of mixed layer models in so-called density coordinates is d iscussed. Density coordinates, or isopycnal coordinates as they are sometim es called, are becoming increasingly popular For use in ocean models due to their highly desirable adiabatic properties. In contrast, almost all exist ing mixed layer models assume a continuous density variable and are therefo re somewhat inconsistent with the density coordinate philosophy. Many exist ing isopycnal models attempt to join standard surface mixed layer models to density coordinate interior models. and it is known that problems can aris e in the physical behavior of the resulting system. The problem of mixed la yer model development is approached here by adopting a density coordinate f ramework at the outset, thereby generating a surface layer model whose cons truction is entirely consistent with that of existing interior density coor dinate models. Examples of quantitative and qualitative behavior are presen ted and argued to be encouraging.