Vertical kinetic energy and turbulent dissipation in the ocean

Abstract

AbstractOceanic internal waves are closely linked to turbulence. Here a relationship between vertical wave number (kz) spectra of fine‐scale vertical kinetic energy (VKE) and turbulent dissipation ε is presented using more than 250 joint profiles from five diverse dynamic regimes, spanning latitudes between the equator and 60°. In the majority of the spectra VKE varies as . Scaling VKE with collapses the off‐equatorial spectra to within but underestimates the equatorial spectrum. The simple empirical relationship between VKE and ε fits the data better than a common shear‐and‐strain fine‐scale parameterization, which significantly underestimates ε in the two data sets that are least consistent with the Garrett‐Munk (GM) model. The new relationship between fine‐scale VKE and dissipation rate can be interpreted as an alternative, single‐parameter scaling for turbulent dissipation in terms of fine‐scale internal wave vertical velocity that requires no reference to the GM model spectrum.