Large-Eddy Simulations of Baroclinic Instability and Turbulent Mixing
Abstract
The long-term goal of this project is to improve our ability to understand, model, and predict lateral mixing and the associated submesoscale physical structure and processes in the upper and interior ocean. The main objective of this project is to examine the interaction between baroclinic, mesoscale eddies and turbulence using a large-eddy simulation (LES) model. Cases will focus on strong, baroclinic waves that form in the mixed layer along surface fronts with scales of a few km, and on mesoscale eddies that are imbedded within larger scale frontal regions. Our goal is to quantify, understand, and ultimately parameterize the physical processes that lead to lateral mixing. Simulations will help guide field experiments planned as part of the Lateral Mixing DRI, and provide a tool for understanding observations in the analysis phase of the project. High-resolution simulations of baroclinic instability and the interaction of mesoscale flow with turbulent mixing are conducted and analyzed using a large-eddy simulation model. Our analysis centers on quantifying and understanding the mechanisms by which small-scale turbulent structure develops on the mesoscale field; the physical processes and balances that control lateral mixing of fluid properties across the unstable front; and the transition from strongly horizontal, geostrophic motion on the mesoscale to three-dimensional, quasi-isotropic, non-hydrostatic motion on turbulent scales. A second area of research that we are investigating concerns the dispersion of dye by mixing in the ocean surface boundary layer. Observations of dye taken from aircraft off the coast of Florida in preliminary experiments suggest that dye patches are capable of outlining mixing circulations contained in the ocean boundary layer. Lateral banding in the dye observations suggests that circulations in the mixed layer are actively concentrating the dye along the wind direction.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 30, 2011
- Accession Number
- ADA557056
Entities
People
- Eric D. Skyllingstad
- Roger M. Samelson
Organizations
- Oregon State University