Dynamics of an Abyssal Circulation Driven by Bottom-Intensified Mixing on Slopes
Author(s)
Callies, Jörn; Ferrari, Raffaele
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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.
Date issued
2018-06Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary SciencesJournal
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
ISSN
1520-0485