Dynamics of an Abyssal Circulation Driven by Bottom-Intensified Mixing on Slopes
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jpo-d-17-0125.1.pdf
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Published version
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Author(s) •
Callies, Jörn
Ferrari, Raffaele
Date Issued
June 2018
Journal
Journal of Physical Oceanography
Publisher
American Meteorological Society
Citation
Callies, Jörn and Raffaele Ferrari, "Dynamics of an Abyssal Circulation Driven by Bottom-Intensified Mixing on Slopes." Journal of Physical Oceanography 48, 6 (June 2018): 1257-82 doi. 10.1175/JPO-D-17-0125.1 ©2018 Authors
Version
Final published version
Abstract
The large-scale circulation of the abyssal ocean is enabled by small-scale diapycnal mixing, which observations suggest is strongly enhanced toward the ocean bottom, where the breaking of internal tides and lee waves is most vigorous. As discussed recently, bottom-intensified mixing induces a pattern of near-bottom upand downwelling that is quite different from the traditionally assumed widespread upwelling. Here the consequences of bottom-intensified mixing for the horizontal circulation of the abyssal ocean are explored by considering planetary geostrophic dynamics in an idealized ''bathtub geometry.'' Up- and downwelling layers develop on bottom slopes as expected, and these layers are well described by boundary layer theory. The basin-scale circulation is driven by flows in and out of these boundary layers at the base of the sloping topography, which creates primarily zonal currents in the interior and a net meridional exchange along western boundaries. The rate of the net overturning is controlled by the up- and downslope transports in boundary layers on slopes and can be predicted with boundary layer theory. ©2018 American Meteorological Society.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
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DOI of Published Version
https://doi.org/10.1175/JPO-D-17-0125.1