Sub-mesoscale Circulation in the Southern Ocean

Event type: 
8 September 2014

Climate Change Research Centre seminar room, Mathews Building, Kensington Campus, Sydney

Isa Rosso
Research School of Earth Sciences, ANU
Climate Change Research Centre

In this talk, I will present results from the first sub-mesoscale-resolving (1/80°) model of the Kerguelen Plateau Region (Indian sector of the Southern Ocean). The model resolution allows to resolve sub-mesoscale filamentary structures (length scale of order 10 km) and to observe spatial inhomogeneity in the sub-mesoscale eddy kinetic energy and vertical velocities. The vertical velocities, which are dramatically higher than in mesoscale-resolving models, strongly enhance the vertical exchange of advected Lagrangian particles. Furthermore, there is evidence that the inhomogeneity in the sub-mesoscale fields is related to the topographic features of this region and that the topography indirectly generates the sub-mesoscale structures: topography controls mesoscale flows, which in turn generate sub-mesoscale activity. Finally, I will show that mesoscale eddy kinetic energy and strain rate can be used, to first order, as a proxy for sub-mesoscale flows, implying a possible route to parameterise sub-mesoscale transport in coarser resolution models.