John Taylor (University of Cambridge)
" Submesoscales in the Southern Ocean
The Southern Ocean plays a central role in the Meridional Overturning Circulation. Here, strong wind-driven flows and energetic eddies facilitate the vertical exchange of water. Near the ocean surface, submesoscale eddies and fronts with scales between 1-10km are associated with enhanced vertical velocity. Despite their importance in other regions, little is known about the role of submesoscales in the Southern Ocean. Here, we will present new observations and numerical simulations of submesoscales in the Southern Ocean. Observations were made as part of the SMILES project from April-May 2015 east of Drake Passage in the Scotia Sea. During the cruise, a large northward meander of the Antarctic Circumpolar Current (ACC) was sampled at high resolution using towed bodies, surface drifters, microstructure, and dye release. Satellite imagery indicated the presence of submesoscale ‘wrinkles’ along the sharp temperature gradient associated with the ACC. Observations using a moving vessel profiler (MVP) reveal rich three-dimensional structure associated with these features. A high resolution regional ocean model exhibits similar features and reveals striking spatial variability in submesoscale activity. A linear stability analysis and nonlinear numerical simulations are used to study the dynamics of these features and their interaction with the ACC jet. "