Forcing of the overturning circulation across a circumpolar channel by internal wave breaking

The hypothesis that the impingement of mesoscale eddy flows on small-scale topography regulates diapycnal mixing and meridional overturning across the deep Southern Ocean is assessed in an idealised model. The model simulates an eddying circumpolar current coupled to a double-celled meridional overt...

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Bibliographic Details
Published in:Journal of Geophysical Research: Oceans
Main Authors: Broadbridge, Maria B., Naveira Garabato, Alberto C., Nurser, A.J. George
Format: Article in Journal/Newspaper
Language:English
Published: 2016
Subjects:
Online Access:http://nora.nerc.ac.uk/id/eprint/513884/
https://nora.nerc.ac.uk/id/eprint/513884/7/jgrc21824.pdf
https://nora.nerc.ac.uk/id/eprint/513884/1/jgrc21824.pdf
https://doi.org/10.1002/2015JC011597
Description
Summary:The hypothesis that the impingement of mesoscale eddy flows on small-scale topography regulates diapycnal mixing and meridional overturning across the deep Southern Ocean is assessed in an idealised model. The model simulates an eddying circumpolar current coupled to a double-celled meridional overturning with properties broadly resembling those of the Southern Ocean circulation, and represents lee wave-induced diapycnal mixing using an online formulation grounded on wave radiation theory. The diapycnal mixing generated by the simulated eddy field is found to play a major role in sustaining the lower overturning cell in the model, and to underpin a significant sensitivity of this cell to wind forcing. The vertical structure of lower overturning is set by mesoscale eddies, which propagate the effects of near-bottom diapycnal mixing by displacing isopycnals vertically.