Boundary Upwelling of Antarctic Bottom Water by Topographic Turbulence
Abstract The lower cell of the meridional overturning circulation (MOC) is sourced by dense Antarctic Bottom Waters (AABWs), which form and sink around Antarctica and subsequently fill the abyssal ocean. For the MOC to “overturn,” these dense waters must upwell via mixing with lighter waters above....
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ftdoajarticles:oai:doaj.org/article:2a99f55cbe684255bfd40c34f5c61934 2023-11-12T04:08:42+01:00 Boundary Upwelling of Antarctic Bottom Water by Topographic Turbulence L. E. Baker A. Mashayek A. C. Naveira Garabato 2023-10-01T00:00:00Z https://doi.org/10.1029/2022AV000858 https://doaj.org/article/2a99f55cbe684255bfd40c34f5c61934 EN eng Wiley https://doi.org/10.1029/2022AV000858 https://doaj.org/toc/2576-604X 2576-604X doi:10.1029/2022AV000858 https://doaj.org/article/2a99f55cbe684255bfd40c34f5c61934 AGU Advances, Vol 4, Iss 5, Pp n/a-n/a (2023) flow‐topography interaction mixing water masses lee waves upwelling Antarctic Bottom Water Geology QE1-996.5 Geophysics. Cosmic physics QC801-809 article 2023 ftdoajarticles https://doi.org/10.1029/2022AV000858 2023-10-29T00:38:24Z Abstract The lower cell of the meridional overturning circulation (MOC) is sourced by dense Antarctic Bottom Waters (AABWs), which form and sink around Antarctica and subsequently fill the abyssal ocean. For the MOC to “overturn,” these dense waters must upwell via mixing with lighter waters above. Here, we investigate the processes underpinning such mixing, and the resulting water mass transformation, using an observationally forced, high‐resolution numerical model of the Drake Passage in the Southern Ocean. In the Drake Passage, the mixing of dense AABW formed in the Weddell Sea with lighter deep waters transported from the Pacific Ocean by the Antarctic Circumpolar Current is catalyzed by energetic flows impinging on rough topography. We find that multiple topographic interaction processes facilitate the mixing of the two water masses, ultimately resulting in the upwelling of waters with neutral density greater than 28.19 kg m−3, and the downwelling of the lighter waters above. In particular, we identify the role of sharp density interfaces between AABW and overlying waters and find that the dynamics of the interfaces' interaction with topography can modify many of the processes that generate mixing. Such sharp interfaces between water masses have been observed in several parts of the global ocean, but are unresolved and unrepresented in climate‐scale ocean models. We suggest that they are likely to play an important role in abyssal dynamics and mixing, and therefore require further exploration. Article in Journal/Newspaper Antarc* Antarctic Antarctica Drake Passage Southern Ocean Weddell Sea Directory of Open Access Journals: DOAJ Articles AGU Advances 4 5 |
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Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
flow‐topography interaction mixing water masses lee waves upwelling Antarctic Bottom Water Geology QE1-996.5 Geophysics. Cosmic physics QC801-809 |
spellingShingle |
flow‐topography interaction mixing water masses lee waves upwelling Antarctic Bottom Water Geology QE1-996.5 Geophysics. Cosmic physics QC801-809 L. E. Baker A. Mashayek A. C. Naveira Garabato Boundary Upwelling of Antarctic Bottom Water by Topographic Turbulence |
topic_facet |
flow‐topography interaction mixing water masses lee waves upwelling Antarctic Bottom Water Geology QE1-996.5 Geophysics. Cosmic physics QC801-809 |
description |
Abstract The lower cell of the meridional overturning circulation (MOC) is sourced by dense Antarctic Bottom Waters (AABWs), which form and sink around Antarctica and subsequently fill the abyssal ocean. For the MOC to “overturn,” these dense waters must upwell via mixing with lighter waters above. Here, we investigate the processes underpinning such mixing, and the resulting water mass transformation, using an observationally forced, high‐resolution numerical model of the Drake Passage in the Southern Ocean. In the Drake Passage, the mixing of dense AABW formed in the Weddell Sea with lighter deep waters transported from the Pacific Ocean by the Antarctic Circumpolar Current is catalyzed by energetic flows impinging on rough topography. We find that multiple topographic interaction processes facilitate the mixing of the two water masses, ultimately resulting in the upwelling of waters with neutral density greater than 28.19 kg m−3, and the downwelling of the lighter waters above. In particular, we identify the role of sharp density interfaces between AABW and overlying waters and find that the dynamics of the interfaces' interaction with topography can modify many of the processes that generate mixing. Such sharp interfaces between water masses have been observed in several parts of the global ocean, but are unresolved and unrepresented in climate‐scale ocean models. We suggest that they are likely to play an important role in abyssal dynamics and mixing, and therefore require further exploration. |
format |
Article in Journal/Newspaper |
author |
L. E. Baker A. Mashayek A. C. Naveira Garabato |
author_facet |
L. E. Baker A. Mashayek A. C. Naveira Garabato |
author_sort |
L. E. Baker |
title |
Boundary Upwelling of Antarctic Bottom Water by Topographic Turbulence |
title_short |
Boundary Upwelling of Antarctic Bottom Water by Topographic Turbulence |
title_full |
Boundary Upwelling of Antarctic Bottom Water by Topographic Turbulence |
title_fullStr |
Boundary Upwelling of Antarctic Bottom Water by Topographic Turbulence |
title_full_unstemmed |
Boundary Upwelling of Antarctic Bottom Water by Topographic Turbulence |
title_sort |
boundary upwelling of antarctic bottom water by topographic turbulence |
publisher |
Wiley |
publishDate |
2023 |
url |
https://doi.org/10.1029/2022AV000858 https://doaj.org/article/2a99f55cbe684255bfd40c34f5c61934 |
genre |
Antarc* Antarctic Antarctica Drake Passage Southern Ocean Weddell Sea |
genre_facet |
Antarc* Antarctic Antarctica Drake Passage Southern Ocean Weddell Sea |
op_source |
AGU Advances, Vol 4, Iss 5, Pp n/a-n/a (2023) |
op_relation |
https://doi.org/10.1029/2022AV000858 https://doaj.org/toc/2576-604X 2576-604X doi:10.1029/2022AV000858 https://doaj.org/article/2a99f55cbe684255bfd40c34f5c61934 |
op_doi |
https://doi.org/10.1029/2022AV000858 |
container_title |
AGU Advances |
container_volume |
4 |
container_issue |
5 |
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1782328929891123200 |