Turbulence and diapycnal mixing in Drake Passage
St. Laurent, Louis C.
Naveira Garabato, Alberto C.
Ledwell, James R.
Thurnherr, Andreas M.
Toole, John M.
Watson, Andrew J.
MetadataShow full item record
Direct measurements of turbulence levels in the Drake Passage region of the Southern Ocean show a marked enhancement over the Phoenix Ridge. At this site, the Antarctic Circumpolar Current (ACC) is constricted in its flow between the southern tip of South America and the northern tip of the Antarctic Peninsula. Observed turbulent kinetic energy dissipation rates are enhanced in the regions corresponding to the ACC frontal zones where strong flow reaches the bottom. In these areas, turbulent dissipation levels reach 10−8 W kg−1 at abyssal and middepths. The mixing enhancement in the frontal regions is sufficient to elevate the diapycnal turbulent diffusivity acting in the deep water above the axis of the ridge to 1 × 10−4 m2 s−1. This level is an order of magnitude larger than the mixing levels observed upstream in the ACC above smoother bathymetry. Outside of the frontal regions, dissipation rates are O(10−10) W kg−1, comparable to the background levels of turbulence found throughout most mid- and low-latitude regions of the global ocean.
Author Posting. © American Meteorological Society, 2012. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 42 (2012): 2143–2152, doi:10.1175/JPO-D-12-027.1.
Suggested CitationArticle: St. Laurent, Louis C., Naveira Garabato, Alberto C., Ledwell, James R., Thurnherr, Andreas M., Toole, John M., Watson, Andrew J., "Turbulence and diapycnal mixing in Drake Passage", Journal of Physical Oceanography 42 (2012): 2143–2152, DOI:10.1175/JPO-D-12-027.1, https://hdl.handle.net/1912/5752
Showing items related by title, author, creator and subject.
Biases in Thorpe-scale estimates of turbulence dissipation. Part I : Assessments from large-scale overturns in oceanographic data Mater, Benjamin D.; Venayagamoorthy, Subhas K.; St. Laurent, Louis C.; Moum, James N. (American Meteorological Society, 2015-10)Oceanic density overturns are commonly used to parameterize the dissipation rate of turbulent kinetic energy. This method assumes a linear scaling between the Thorpe length scale LT and the Ozmidov length scale LO. Historic ...
Waterman, Stephanie N.; Naveira Garabato, Alberto C.; Polzin, Kurt L. (American Meteorological Society, 2013-02)This study reports on observations of turbulent dissipation and internal wave-scale flow properties in a standing meander of the Antarctic Circumpolar Current (ACC) north of the Kerguelen Plateau. The authors characterize ...
Waterman, Stephanie N.; Polzin, Kurt L.; Naveira Garabato, Alberto C.; Sheen, Katy L.; Forryan, Alexander (American Meteorological Society, 2014-05)Simultaneous full-depth microstructure measurements of turbulence and finestructure measurements of velocity and density are analyzed to investigate the relationship between turbulence and the internal wave field in the ...