The Antarctic Circumpolar Current (ACC) in the Southern Ocean is the world's largest, and arguably most influential, ocean current, and serves as the principal pathway of exchange between ocean basins. The Southern Ocean is also the primary region where anthropogenic carbon dioxide enters the ocean from the atmosphere and is central to our understanding of how the climate is responding to anthropogenic forcing.

Ocean eddies are a ubiquitous feature and play a particularly pivotal role in the dynamics and thermodynamics of the Southern Ocean. Although progress has been made in the last decade, many aspects of eddies remain poorly understood, rendering it difficult to faithfully parameterise their effects in climate models. Recent studies suggest that the ability of eddies to mix heat, salt, carbon and other properties in the Southern Ocean is somewhat suppressed in the surface layer by the presence the ACC, but strongly enhanced at mid depth where there are "critical layers". However, the underlying mechanisms are far from being understood, and there is an ongoing debate concerning whether the Southern Ocean is a barrier or blender for eddy mixing. 

This PhD project aims to improve our understanding of how the eddies mix properties in the Southern Ocean,  which, in turn, help to guide future eddy parameterizations in climate models. You will join an active research team of mathematicians and physical oceanographers. The primary tool to tackle the project is a combination of theory and numerical models of different complexity. You may also have the opportunity to participate in research cruises to make relevant measurements to test your theory and model results.

Marshall, J., E. Shuckburgh, H. Jones, and C. Hill (2006), Estimates and implications of surface eddy diffusivity in the Southern Ocean derived from tracer transport, Journal of Physical Oceanography, 36, 1806–1821.

Smith, K. S., and J. Marshall (2009), Evidence for enhanced eddy mixing at middepth in the Southern Ocean, Journal Physical Oceanography, 39, 50–69.

Ferrari, R., and M. Nikurashin (2010), Suppression of eddy mixing across jets in the southern ocean, Journal of Physical Oceanography, 40, 1501–1519.

Naveira Garabato, A. C., R. Ferrari, and K. L. Polzin (2011), Eddy stirring in the Southern Ocean, Journal of Geophysical Research, 116, C09019, doi:10.1029/2010JC006818.