Parameterizing the Effects of Small-Scale Mixing in Large-Scale Numerical Models

Abstract

This paper first reviews some results from the field of small-scale turbulence measurement. Features which are of particular importance to the ways in which the effects of turbulent mixing are incorporated in large-scale numerical ocean models are the following: the relation between mixing and “mean” shear, the potential for variable mixing efficiency, and the possibility that diffusivities differ for heat (temperature) and salt. The next section reviews the process(es) of deriving values for the constant diffusivity coefficients which are presently used in most numerical ocean models, while a final section explores effects of using instead variable diffusivities, modelling these roughly on results of the past decade of work on ocean microscales.