A Turbulence Velocity Scale for Predicting the Fate of Buoyant Materials in the Oceanic Mixed Layer

Abstract

We introduce a general framework to predict the fate of buoyant materials in the oceanic mixed layer. The framework is based on the estimation of a turbulence velocity scale for the vertical mixing of buoyant materials. By combining this velocity scale with the material's terminal rise velocity and a K-profile parameterization, we are able to derive an analytical prediction for the vertical profile of material concentration that is shown to be a reasonably accurate and general representation for oceanic mixed layer regimes driven by various levels of wind shear, Stokes drift, and buoyancy flux. The analytically predicted profile allows us to estimate relevant parameters for the fate of buoyant materials, such as the depth of a plume's center of mass and the horizontal transport. We show that the predictions agree with large-eddy simulations driven by various combinations of wind shear, Stokes drift, and buoyancy fluxes.