Topographic enhancement of vertical turbulent mixing in the Southern Ocean
© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 8 (2017): 14197, doi:10.1038/ncomms14197. It is an open question whether turbulent mixing across density surfaces is sufficien...
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ftwhoas:oai:darchive.mblwhoilibrary.org:1912/8823 2023-05-15T16:02:33+02:00 Topographic enhancement of vertical turbulent mixing in the Southern Ocean Mashayek, Ali Ferrari, Raffaele Merrifield, Sophia T. Ledwell, James R. St. Laurent, Louis C. Naveira Garabato, Alberto C. 2017-03-06 https://hdl.handle.net/1912/8823 en_US eng Nature Publishing Group https://doi.org/10.1038/ncomms14197 Nature Communications 8 (2017): 14197 https://hdl.handle.net/1912/8823 doi:10.1038/ncomms14197 Attribution 4.0 International http://creativecommons.org/licenses/by/4.0/ CC-BY Nature Communications 8 (2017): 14197 doi:10.1038/ncomms14197 Article 2017 ftwhoas https://doi.org/10.1038/ncomms14197 2022-05-28T22:59:52Z © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 8 (2017): 14197, doi:10.1038/ncomms14197. It is an open question whether turbulent mixing across density surfaces is sufficiently large to play a dominant role in closing the deep branch of the ocean meridional overturning circulation. The diapycnal and isopycnal mixing experiment in the Southern Ocean found the turbulent diffusivity inferred from the vertical spreading of a tracer to be an order of magnitude larger than that inferred from the microstructure profiles at the mean tracer depth of 1,500 m in the Drake Passage. Using a high-resolution ocean model, it is shown that the fast vertical spreading of tracer occurs when it comes in contact with mixing hotspots over rough topography. The sparsity of such hotspots is made up for by enhanced tracer residence time in their vicinity due to diffusion toward weak bottom flows. The increased tracer residence time may explain the large vertical fluxes of heat and salt required to close the abyssal circulation. Financial support for A.M. and R.F. under the US National Science Foundation grant OCE-1233832 is gratefully acknowledged. A.M. also acknowledges support from an NSERC PDF award. Article in Journal/Newspaper Drake Passage Southern Ocean Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) Drake Passage Southern Ocean Nature Communications 8 1 |
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Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) |
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English |
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© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 8 (2017): 14197, doi:10.1038/ncomms14197. It is an open question whether turbulent mixing across density surfaces is sufficiently large to play a dominant role in closing the deep branch of the ocean meridional overturning circulation. The diapycnal and isopycnal mixing experiment in the Southern Ocean found the turbulent diffusivity inferred from the vertical spreading of a tracer to be an order of magnitude larger than that inferred from the microstructure profiles at the mean tracer depth of 1,500 m in the Drake Passage. Using a high-resolution ocean model, it is shown that the fast vertical spreading of tracer occurs when it comes in contact with mixing hotspots over rough topography. The sparsity of such hotspots is made up for by enhanced tracer residence time in their vicinity due to diffusion toward weak bottom flows. The increased tracer residence time may explain the large vertical fluxes of heat and salt required to close the abyssal circulation. Financial support for A.M. and R.F. under the US National Science Foundation grant OCE-1233832 is gratefully acknowledged. A.M. also acknowledges support from an NSERC PDF award. |
format |
Article in Journal/Newspaper |
author |
Mashayek, Ali Ferrari, Raffaele Merrifield, Sophia T. Ledwell, James R. St. Laurent, Louis C. Naveira Garabato, Alberto C. |
spellingShingle |
Mashayek, Ali Ferrari, Raffaele Merrifield, Sophia T. Ledwell, James R. St. Laurent, Louis C. Naveira Garabato, Alberto C. Topographic enhancement of vertical turbulent mixing in the Southern Ocean |
author_facet |
Mashayek, Ali Ferrari, Raffaele Merrifield, Sophia T. Ledwell, James R. St. Laurent, Louis C. Naveira Garabato, Alberto C. |
author_sort |
Mashayek, Ali |
title |
Topographic enhancement of vertical turbulent mixing in the Southern Ocean |
title_short |
Topographic enhancement of vertical turbulent mixing in the Southern Ocean |
title_full |
Topographic enhancement of vertical turbulent mixing in the Southern Ocean |
title_fullStr |
Topographic enhancement of vertical turbulent mixing in the Southern Ocean |
title_full_unstemmed |
Topographic enhancement of vertical turbulent mixing in the Southern Ocean |
title_sort |
topographic enhancement of vertical turbulent mixing in the southern ocean |
publisher |
Nature Publishing Group |
publishDate |
2017 |
url |
https://hdl.handle.net/1912/8823 |
geographic |
Drake Passage Southern Ocean |
geographic_facet |
Drake Passage Southern Ocean |
genre |
Drake Passage Southern Ocean |
genre_facet |
Drake Passage Southern Ocean |
op_source |
Nature Communications 8 (2017): 14197 doi:10.1038/ncomms14197 |
op_relation |
https://doi.org/10.1038/ncomms14197 Nature Communications 8 (2017): 14197 https://hdl.handle.net/1912/8823 doi:10.1038/ncomms14197 |
op_rights |
Attribution 4.0 International http://creativecommons.org/licenses/by/4.0/ |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1038/ncomms14197 |
container_title |
Nature Communications |
container_volume |
8 |
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1 |
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1766398210177236992 |