Diapycnal Mixing in the Antarctic Circumpolar CurrentSource: Journal of Physical Oceanography:;2010:;Volume( 041 ):;issue: 001::page 241DOI: 10.1175/2010JPO4557.1Publisher: American Meteorological Society
Abstract: The vertical dispersion of a tracer released on a density surface near 1500-m depth in the Antarctic Circumpolar Current west of Drake Passage indicates that the diapycnal diffusivity, averaged over 1 yr and over tens of thousands of square kilometers, is (1.3 ± 0.2) ? 10?5 m2 s?1. Diapycnal diffusivity estimated from turbulent kinetic energy dissipation measurements about the area occupied by the tracer in austral summer 2010 was somewhat less, but still within a factor of 2, at (0.75 ± 0.07) ? 10?5 m2 s?1. Turbulent diapycnal mixing of this intensity is characteristic of the midlatitude ocean interior, where the energy for mixing is believed to derive from internal wave breaking. Indeed, despite the frequent and intense atmospheric forcing experienced by the Southern Ocean, the amplitude of finescale velocity shear sampled about the tracer was similar to background amplitudes in the midlatitude ocean, with levels elevated to only 20%?50% above the Garrett?Munk reference spectrum. These results add to a long line of evidence that diapycnal mixing in the interior middepth ocean is weak and is likely too small to dictate the middepth meridional overturning circulation of the ocean.
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contributor author | Ledwell, J. R. | |
contributor author | St. Laurent, L. C. | |
contributor author | Girton, J. B. | |
contributor author | Toole, J. M. | |
date accessioned | 2017-06-09T16:37:08Z | |
date available | 2017-06-09T16:37:08Z | |
date copyright | 2011/01/01 | |
date issued | 2010 | |
identifier issn | 0022-3670 | |
identifier other | ams-71036.pdf | |
identifier uri | http://onlinelibrary.yabesh.ir/handle/yetl/4212884 | |
description abstract | The vertical dispersion of a tracer released on a density surface near 1500-m depth in the Antarctic Circumpolar Current west of Drake Passage indicates that the diapycnal diffusivity, averaged over 1 yr and over tens of thousands of square kilometers, is (1.3 ± 0.2) ? 10?5 m2 s?1. Diapycnal diffusivity estimated from turbulent kinetic energy dissipation measurements about the area occupied by the tracer in austral summer 2010 was somewhat less, but still within a factor of 2, at (0.75 ± 0.07) ? 10?5 m2 s?1. Turbulent diapycnal mixing of this intensity is characteristic of the midlatitude ocean interior, where the energy for mixing is believed to derive from internal wave breaking. Indeed, despite the frequent and intense atmospheric forcing experienced by the Southern Ocean, the amplitude of finescale velocity shear sampled about the tracer was similar to background amplitudes in the midlatitude ocean, with levels elevated to only 20%?50% above the Garrett?Munk reference spectrum. These results add to a long line of evidence that diapycnal mixing in the interior middepth ocean is weak and is likely too small to dictate the middepth meridional overturning circulation of the ocean. | |
publisher | American Meteorological Society | |
title | Diapycnal Mixing in the Antarctic Circumpolar Current | |
type | Journal Paper | |
journal volume | 41 | |
journal issue | 1 | |
journal title | Journal of Physical Oceanography | |
identifier doi | 10.1175/2010JPO4557.1 | |
journal fristpage | 241 | |
journal lastpage | 246 | |
tree | Journal of Physical Oceanography:;2010:;Volume( 041 ):;issue: 001 | |
contenttype | Fulltext |