Mean Vertical Distribution of the Dissipation Rate of Turbulent Energy in the Black Sea. Comparison with the Existing Models

Abstract

We compare the results obtained by using theoretical and semiempirical models developed for the evaluation of the dissipation rate of turbulent energy ε in a stratified ocean with independent distribution of this quantity established by the authors for the active layer of the Black Sea (50–300 m) by using a one-dimensional model taking into account the balance of heat, salt, and fluid inside the layer. It is shown that, in a layer with gradual variation of the Väisälä–Brunt frequency N as a function of depth, the predominant “sink” of the energy of motion into dissipation ε ∼ N 2 is ensured by the flow of energy through the spectrum of internal waves toward low frequencies and small vertical scales. On the contrary, in layers with abrupt drops of density as a function of depth (layers with “jumps of density”), an important role is played by the interface-type waves and the dependence of ε on N transforms into ε ∼ N .