Evolution of Small-Scale Turbulence in a Stratified Shear Flow, Affected by Interplay of the Kinetic and Potential Turbulent Energies

As known, the most energy-dense turbulence in the ocean occurs in its upper layer and it actively interacts with mesoscale motions. We study the evolution of a turbulent layer in stratified ocean using the theory of unsteady turbulent flows in a stratified fluid. The theory starts from a kinetic equation for turbulence parameters and results in the set of equations involving the mutual transformation of the kinetic and potential energies of turbulence that is shown to significantly affect the overall dynamics of energy exchange between small-scale turbulence and mesoscale motions and the formation of the upper mixed layer. Notably, the transformation between kinetic and potential energies eliminates the restriction on the existence of turbulence at large Richardson numbers. The results are applied to the analysis of in situ data for turbulence evolution under the action of shear flows and internal waves, obtained in different areas.