Wave breaking effects are important in many areas of atmospheric and ocean sciences, including air-sea interaction and momentum, energy and biogeochemical fluxes; hurricane dynamics and thermodynamics; pollutant transport and dispersion; aerosol production and ocean acoustics, to name a few. The goal of this collaborative research is to build a stochastic Lagrangian parameterization of surface wave breaking that can subsequently be applied to wave and ocean modeling. The students and postdoctoral researchers employed in this project will gain experience in the disciplines of science, technology, engineering and mathematics (STEM). The data and breaking parameterization developed here will subsequently find direct application in atmosphere and ocean modeling.
Increases in the fidelity and resolution of ocean models, specifically those focused on the sub-mesoscales, require improved representation of surface wave processes. In addition to the importance of wave breaking in the dynamics of wave-current interaction, it also plays an important role in mass transport beyond that represented in classical theories of Stokes drift; in the dynamics and kinematics of Langmuir turbulence; and, more generally, in the transport and dispersion of tracers and pollutants. This research involves laboratory experiments to measure the Lagrangian displacement and velocity of fluid particles in breaking waves. The data will then be used to develop and parameterize a stochastic ordinary differential equation, within the class of Langevin equations, to describe the Lagrangian motion of the fluid elements. The parameterization will be constrained by the n-point structure functions for the experimentally obtained particle paths, which are comparatively easier to obtain and to relate to a stochastic ordinary (Lagrangian) differential equation, when compared to obtaining the n-point structure function of an (Eulerian) stochastic partial differential equation. Given the Lagrangian model, a projection to the Eulerian frame will be used to obtain the dynamical representation of breaking for wave-current interaction and other mixed-layer processes.
