Damping of climate-scale oceanic variability by mesoscale eddy turbulence

Type Article
Date 2021-01
Language English
Author(s) Sévellec Florian1, Naveira Garabato A. C.2, Huck Thierry
Affiliation(s) 1 : Laboratoire d'Océanographie Physique et Spatiale, Univ-Brest CNRS IRD Ifremer, Brest, France
2 : Ocean and Earth Science, University of Southampton, Southampton, UK
Source Journal Of Physical Oceanography (0022-3670) (American Meteorological Society), 2021-01 , Vol. 51 , N. 2 , P. 491-503
DOI 10.1175/JPO-D-20-0141.1
WOS© Times Cited 6
Note This article is included in the The Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean (DIMES) Special Collection.
Keyword(s) Ocean, Southern Ocean, Eddies, Large-scale motions, Nonlinear dynamics, In situ oceanic observations

The impact of mesoscale eddy turbulence on long-term, climatic variability in the ocean's buoyancy structure is investigated using observations from a mooring deployed in the Drake Passage, Southern Ocean. By applying the Temporal-Residual-Mean framework and characterizing the variance contributors and the buoyancy variance budget, we identify the main source and sink of long-term buoyancy variance. Long-term buoyancy variance amplitude is set by long-term vertical velocity fluctuations acting on the steady stratification. This baro-clinic buoyancy flux is also the main source of the variance, indicative of the effect of large-scale baroclinic instability. This source is balanced by a sink of long-term buoyancy variance associated with the vertical advection of the steady stratification by the eddy-induced circulation. We conclude that mesoscale eddy turbulence acts as a damping mechanism for long-term, climatic variability in the region of the observations, consistent with an ‘eddy saturated’ behaviour of the Antarctic Circumpolar Current.

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