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Radiation and Dissipation of Internal Waves Generated by Geostrophic Motions Impinging on Small-Scale Topography: Theory
Citation
Nikurashin, M and Ferrari, R, Radiation and Dissipation of Internal Waves Generated by Geostrophic Motions Impinging on Small-Scale Topography: Theory, Journal of Physical Oceanography, 40, (May) pp. 1055-1074. ISSN 0022-3670 (2010) [Refereed Article]
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Copyright Statement
© Copyright 2010 AMS
DOI: doi:10.1175/2009JPO4199.1
Abstract
Observations and inverse models suggest that small-scale turbulent mixing is enhanced in the Southern
Ocean in regions above rough topography. The enhancement extends O(1) km above the topography, suggesting
that mixing is supported by the breaking of gravity waves radiated from the ocean bottom. In this
study, it is shown that the observed mixing rates can be sustained by internal waves generated by geostrophic
motions flowing over bottom topography. Weakly nonlinear theory is used to describe the internal wave
generation and the feedback of the waves on the zonally averaged flow. Vigorous inertial oscillations are
driven at the ocean bottom by waves generated at steep topography. The wave radiation and dissipation at
equilibrium is therefore the result of both geostrophic flow and inertial oscillations differing substantially
from the classical lee-wave problem. The theoretical predictions are tested versus two-dimensional highresolution
numerical simulations with parameters representative of Drake Passage. This work suggests that
mixing in Drake Passage can be supported by geostrophic motions impinging on rough topography rather
than by barotropic tidal motions, as is commonly assumed.
Item Details
Item Type: | Refereed Article |
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Keywords: | ocean mixing, internal waves, lee waves, eddies, rough topography |
Research Division: | Earth Sciences |
Research Group: | Oceanography |
Research Field: | Physical oceanography |
Objective Division: | Environmental Policy, Climate Change and Natural Hazards |
Objective Group: | Understanding climate change |
Objective Field: | Climate change models |
UTAS Author: | Nikurashin, M (Dr Maxim Nikurashin) |
ID Code: | 79715 |
Year Published: | 2010 |
Web of Science® Times Cited: | 106 |
Deposited By: | IMAS Research and Education Centre |
Deposited On: | 2012-10-01 |
Last Modified: | 2012-11-26 |
Downloads: | 0 |
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