Turbulent Fluid Dynamics at the Margins of Rotational and Stratified Control:
Submesoscale Fluid Dynamics in the Ocean

Dr. James C. McWilliams
Louis B. Slichter Professor of Earth Sciences
University of California, Los Angeles
Institute of Geophysics and Planetary Physics and
Department of Atmospheric and Oceanic Sciences

Geophysical fluid dynamicists have developed a mature perspective on the dynamical influence of Earth's rotation, while most other areas of fluid dynamics can safely disregard rotation. Similarly, geophysical problems usually arise under the influence of stable density stratification at least as importantly as velocity shear. In this talk the dominant turbulence and wave behaviors in the rotating and non-rotating, stratified and non-stratified fluid-dynamical realms are described, and particular attention is given to their borderlands, where rotational and stratified influences are significant but not dominant. Contrary to the inverse energy cascade of geostrophic turbulence toward larger scales, a forward energy cascade develops within the borderlands from the breakdown of diagnostic force balances, frontogenesis and frontal instabilities, and filamentogenesis with strong surface convergences. Then the cascade continues further through the small-scale, non-rotating, unstratified (a.k.a. universal) realm until it dissipates at the microscale. In particular, this submesoscale cascade behavior is of interest as a global route to kinetic and available-potential energy dissipations in the oceanic general circulation, as well as an energy source for microscale material mixing across stably-stratified density surfaces and a penetration route for potential vorticity across stably stratified density surfaces.

April 16, 2009, Thurday

Seminar: 3:30-4:30pm

***Special Reception: 3:00pm (Everyone Welcome)***

Computer and Space Sciences (CSS) Building, Auditorium (Room 2400)

[Contact: Kayo Ide]
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