Modification of turbulent dissipation rates by a deep Southern Ocean eddy

Sheen, K.L.; Brearley, J.A.; Naveira Garabato, A.C.; Smeed, D.A. ORCID:; St. Laurent, L.; Meredith, M.P. ORCID:; Thurnherr, A.M.; Waterman, S.N.. 2015 Modification of turbulent dissipation rates by a deep Southern Ocean eddy. Geophysical Research Letters, 42 (9). 3450-3457.

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The impact of a mesoscale eddy on the magnitude and spatial distribution of diapycnal ocean mixing is investigated using a set of hydrographic and microstructure measurements collected in the Southern Ocean. These data sampled a baroclinic, mid-depth eddy formed during the disintegration of a deep boundary current. Turbulent dissipation is suppressed within the eddy, but is elevated by up to an order of magnitude along the upper and lower eddy boundaries. A ray-tracing approximation is employed asa heuristic device to elucidate how the internal wave field evolves in the ambient velocity and stratification conditions accompanying the eddy. These calculations are consistent with the observations, suggesting reflection of internal wave energy from the eddy center and enhanced breaking through critical layer processes along the eddy boundaries. These results have important implications for understanding where and how internal wave energy is dissipated in the presence of energetic deep geostrophic flows.

Item Type: Publication - Article
Digital Object Identifier (DOI):
Programmes: BAS Programmes > Polar Science for Planet Earth (2009 - ) > Polar Oceans
BAS Programmes > BAS Programmes 2015 > Polar Oceans
ISSN: 0094-8276
Additional Keywords: mixing; eddy; turbulent dissipation; internal waves; southern ocean; ray tracing
Date made live: 28 Apr 2015 10:53 +0 (UTC)

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