Damping of climate-scale oceanic variability by mesoscale eddy turbulence

International audience 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 characterizin...

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Bibliographic Details
Published in:Journal of Physical Oceanography
Main Authors: Sévellec, Florian, Naveira Garabato, Alberto, Huck, Thierry
Other Authors: Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Interdisciplinary Graduate School for the Blue planet (ISblue), ANR-17-EURE-0015,ISBlue,Interdisciplinary Graduate School for the Blue planet(2017)
Format: Article in Journal/Newspaper
Language:English
Published: HAL CCSD 2021
Subjects:
Ocean
Southern Ocean
Eddies
Large-scale motions
Nonlinear dynamics
In situ oceanic observations
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean
Atmosphere
Antarctic
Drake Passage
The Antarctic
Antarc*
Online Access:https://hal.science/hal-03004064
https://hal.science/hal-03004064/document
https://hal.science/hal-03004064/file/Sevellec_et_al_JPO2020inpress.pdf
https://doi.org/10.1175/JPO-D-20-0141.1
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Summary:International audience 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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