Mixed-layer dynamics and buoyancy transports

Abstract

Ocean mixed layer (ML) dynamics are considered in the framework of a self-similar buoyancy profile governed by the Kraus-Turner budgets. The global validity of the profile is suggested by an inspection of Levitus-data. A parameterization of the mechanical energy forcing in terms of surface winds and heat fluxes is tested against weathership data in 1-dimensional (1D) model experiments. The ML-model is furthermore incorporated into a 3D transport-theory, where the consideration of 2 transport equations accounts for the Kraus-Turner concept. To test the transport theory, relative geostrophic velocities are derived from buoyancy-data. In addition to ML-dynamics, the empirical buoyancy-profile provides a convenient representation of this velocity field. For the mid-latitude Pacific, it is shown that these velocities, in conjunction with observed surface velocities, yield a realistic estimate of advective buoyancy-fluxes.