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Article Dans Une Revue Journal of Physical Oceanography Année : 2011

Mixed Layer Lateral Eddy Fluxes Mediated by Air-Sea Interaction.

Résumé

The modulation of air-sea heat fluxes by geostrophic eddies due to the stirring of temperature at the sea surface is discussed and quantified. It is argued that the damping of eddy temperature variance by such air-sea fluxes enhances the dissipation of surface temperature fields. Depending on the time scale of damping relative to that of the eddying motions, surface eddy diffusivities can be significantly enhanced over interior values. The issues are explored and quantified in a controlled setting by driving a tracer field, a proxy for sea surface temperature, with surface altimetric observations in the Antarctic Circumpolar Current (ACC) of the Southern Ocean. A new, tracer-based diagnostic of eddy diffusivity is introduced, which is related to the Nakamura effective diffusivity. Using this, the mixed layer lateral eddy diffusivities associated with (i) eddy stirring and small-scale mixing and (ii) surface damping by air-sea interaction is quantified. In the ACC, a diffusivity associated with surface damping of a comparable magnitude to that associated with eddy stirring (500 m2 s−1) is found. In frontal regions prevalent in the ACC, an augmentation of surface lateral eddy diffusivities of this magnitude is equivalent to an air-sea flux of 100 W m−2 acting over a mixed layer depth of 100 m, a very significant effect. Finally, the implications for other tracer fields such as salinity, dissolved gases, and chlorophyll are discussed. Different tracers are found to have surface eddy diffusivities that differ significantly in magnitude.

Mots clés

Domaines

Océanographie

Dates et versions

hal-00588862 , version 1 (26-04-2011)

Identifiants

Citer

Emily Shuckburgh, Guillaume Maze, David Ferreira, John Marshall, Helen Jones, et al.. Mixed Layer Lateral Eddy Fluxes Mediated by Air-Sea Interaction.. Journal of Physical Oceanography, 2011, 41 (1), pp.130-144. ⟨10.1175/2010JPO4429.1⟩. ⟨hal-00588862⟩
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