Further refinements to models for the bulk-skin sea surface temperature difference

The authors set the basis for a new physical model of renewal type, and propose a parameterization for the temperature difference across the cool skin of the ocean in which the effects of thermal buoyancy, wind stress, and microscale breaking are all integrated by means of the appropriate renewal time scales. Ideally, they seek to obtain a model that will accurately apply under a wide variety of environmental conditions. The physical processes that govern the magnitude of ΔT can vary with environmental conditions. Three different possible mechanisms are shown. These mechanisms include free convection, forced convection driven by wind shear stress, and forced convection drive by microscale wave breaking. During free convection the turbulent transport of heat is buoyancy-driven. Since the cool skin is denser than the underlying water it will become gravitationally unstable and tend to sink. Evaporation generates a salinity gradient which also contributes to the gravitational instability. During free convection, mean flow and wind shear stress are absent (non-existent or very low winds). As a result, ΔT is controlled primarily by the net heat flux