PhD Transfer Exam | Rosalie Cormier, Simulating Baroclinic Instability in the Beaufort Gyre

Friday, August 9, 2024 11:00 am - 12:00 pm EDT (GMT -04:00)

Location

MC 6460

Candidate

Rosalie Cormier | Applied Math, University of Waterloo

Title

Simulating Baroclinic Instability in the Beaufort Gyre

Abstract

The Beaufort Gyre (BG) is a large region of approximately geostrophic circulation in the Arctic Ocean. Surface wind-forcing maintains a vertical shear in the gyre's velocity, giving rise to baroclinic instability, while its typical density distribution is such that the BG stores available potential energy. Perturbations to the unstable background state may self-amplify, converting available potential energy into kinetic energy. The growing perturbation equilibrates as a field of baroclinic eddies, whose collective effect is to mix the BG before losing momentum through viscous dissipation. My graduate research focuses on using large-eddy simulations of an idealized model of the BG to determine the effects of variable wind-forcing on baroclinic instability and, furthermore, to determine the effects of baroclinic-eddy development, propagation, and dissipation on the stratification of the gyre. I will discuss my idealized model of the BG and the choices I have made in my numerical implementation, including the domain geometry, the discretization of spatial and temporal operators, and the turbulence closure I use. I will present preliminary simulation results, and I will then discuss my proposal to extend my research into a doctoral thesis project. By extending the scope of my project, I intend to improve the realism of my gyre model by incorporating other significant features of the BG, such as sea ice. I also intend to explore the effects of alternative parameterizations of wind-forcing and of energy dissipation on the dynamics of the simulated fields.