On the consumption of Antarctic Bottom Water in the abyssal ocean
The abyssal ocean is primarily filled by cold, dense waters formed around Antarctica and collectively referred to as Antarctic Bottom Water (AABW). At steady state, AABW must be consumed in the ocean interior at the same rate it is produced, but how and where this consumption is achieved remains poo...
Published in: | Journal of Physical Oceanography |
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ftnerc:oai:nora.nerc.ac.uk:512784 2023-05-15T13:49:32+02:00 On the consumption of Antarctic Bottom Water in the abyssal ocean de Lavergne, Casimir Madec, Gurvan Le Sommer, Julien Nurser, A.J. George Naveira Garabato, Alberto C. 2016-02 text http://nora.nerc.ac.uk/id/eprint/512784/ https://nora.nerc.ac.uk/id/eprint/512784/7/jpo-d-14-0201%252E1.pdf https://nora.nerc.ac.uk/id/eprint/512784/1/jpo-d-14-0201%252E1.pdf https://doi.org/10.1175/JPO-D-14-0201.1 en eng https://nora.nerc.ac.uk/id/eprint/512784/7/jpo-d-14-0201%252E1.pdf https://nora.nerc.ac.uk/id/eprint/512784/1/jpo-d-14-0201%252E1.pdf de Lavergne, Casimir; Madec, Gurvan; Le Sommer, Julien; Nurser, A.J. George; Naveira Garabato, Alberto C. 2016 On the consumption of Antarctic Bottom Water in the abyssal ocean. Journal of Physical Oceanography, 46 (2). 635-661. https://doi.org/10.1175/JPO-D-14-0201.1 <https://doi.org/10.1175/JPO-D-14-0201.1> Marine Sciences Publication - Article PeerReviewed 2016 ftnerc https://doi.org/10.1175/JPO-D-14-0201.1 2023-02-04T19:42:39Z The abyssal ocean is primarily filled by cold, dense waters formed around Antarctica and collectively referred to as Antarctic Bottom Water (AABW). At steady state, AABW must be consumed in the ocean interior at the same rate it is produced, but how and where this consumption is achieved remains poorly understood. Here, we present estimates of abyssal water mass transformation by geothermal heating and parameterized internal wave-driven mixing. We use maps of the energy input to internal waves by tidal and geostrophic motions interacting with topography combined with assumptions about the distribution of energy dissipation to evaluate dianeutral transports induced by breaking internal tides and lee waves. Geothermal transformation is assessed based on a map of geothermal heat fluxes. Under the hypotheses underlying the constructed climatologies of buoyancy fluxes, we calculate that locally-dissipating internal tides and geothermal heating contribute respectively about 8 and 5 Sv of AABW consumption (upwelling), mostly north of 30°S. In contrast, parameterized lee wave-driven mixing causes significant transformation only in the Southern Ocean, where it forms about 3 Sv of AABW, decreasing the mean density but enhancing the northward flow of abyssal waters. The possible role of remotely-dissipating internal tides in complementing AABW consumption is explored based on idealized distributions of mixing energy. Depending mostly on the chosen vertical structure, such mixing could drive 1 to 28 Sv of additional AABW upwelling, highlighting the need to better constrain the spatial distribution of remote dissipation. Though they carry large uncertainties, these climatological transformation estimates shed light on the qualitative functioning and key unknowns of the diabatic overturning. Article in Journal/Newspaper Antarc* Antarctic Antarctica Southern Ocean Natural Environment Research Council: NERC Open Research Archive Antarctic Southern Ocean Journal of Physical Oceanography 46 2 635 661 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
English |
topic |
Marine Sciences |
spellingShingle |
Marine Sciences de Lavergne, Casimir Madec, Gurvan Le Sommer, Julien Nurser, A.J. George Naveira Garabato, Alberto C. On the consumption of Antarctic Bottom Water in the abyssal ocean |
topic_facet |
Marine Sciences |
description |
The abyssal ocean is primarily filled by cold, dense waters formed around Antarctica and collectively referred to as Antarctic Bottom Water (AABW). At steady state, AABW must be consumed in the ocean interior at the same rate it is produced, but how and where this consumption is achieved remains poorly understood. Here, we present estimates of abyssal water mass transformation by geothermal heating and parameterized internal wave-driven mixing. We use maps of the energy input to internal waves by tidal and geostrophic motions interacting with topography combined with assumptions about the distribution of energy dissipation to evaluate dianeutral transports induced by breaking internal tides and lee waves. Geothermal transformation is assessed based on a map of geothermal heat fluxes. Under the hypotheses underlying the constructed climatologies of buoyancy fluxes, we calculate that locally-dissipating internal tides and geothermal heating contribute respectively about 8 and 5 Sv of AABW consumption (upwelling), mostly north of 30°S. In contrast, parameterized lee wave-driven mixing causes significant transformation only in the Southern Ocean, where it forms about 3 Sv of AABW, decreasing the mean density but enhancing the northward flow of abyssal waters. The possible role of remotely-dissipating internal tides in complementing AABW consumption is explored based on idealized distributions of mixing energy. Depending mostly on the chosen vertical structure, such mixing could drive 1 to 28 Sv of additional AABW upwelling, highlighting the need to better constrain the spatial distribution of remote dissipation. Though they carry large uncertainties, these climatological transformation estimates shed light on the qualitative functioning and key unknowns of the diabatic overturning. |
format |
Article in Journal/Newspaper |
author |
de Lavergne, Casimir Madec, Gurvan Le Sommer, Julien Nurser, A.J. George Naveira Garabato, Alberto C. |
author_facet |
de Lavergne, Casimir Madec, Gurvan Le Sommer, Julien Nurser, A.J. George Naveira Garabato, Alberto C. |
author_sort |
de Lavergne, Casimir |
title |
On the consumption of Antarctic Bottom Water in the abyssal ocean |
title_short |
On the consumption of Antarctic Bottom Water in the abyssal ocean |
title_full |
On the consumption of Antarctic Bottom Water in the abyssal ocean |
title_fullStr |
On the consumption of Antarctic Bottom Water in the abyssal ocean |
title_full_unstemmed |
On the consumption of Antarctic Bottom Water in the abyssal ocean |
title_sort |
on the consumption of antarctic bottom water in the abyssal ocean |
publishDate |
2016 |
url |
http://nora.nerc.ac.uk/id/eprint/512784/ https://nora.nerc.ac.uk/id/eprint/512784/7/jpo-d-14-0201%252E1.pdf https://nora.nerc.ac.uk/id/eprint/512784/1/jpo-d-14-0201%252E1.pdf https://doi.org/10.1175/JPO-D-14-0201.1 |
geographic |
Antarctic Southern Ocean |
geographic_facet |
Antarctic Southern Ocean |
genre |
Antarc* Antarctic Antarctica Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctica Southern Ocean |
op_relation |
https://nora.nerc.ac.uk/id/eprint/512784/7/jpo-d-14-0201%252E1.pdf https://nora.nerc.ac.uk/id/eprint/512784/1/jpo-d-14-0201%252E1.pdf de Lavergne, Casimir; Madec, Gurvan; Le Sommer, Julien; Nurser, A.J. George; Naveira Garabato, Alberto C. 2016 On the consumption of Antarctic Bottom Water in the abyssal ocean. Journal of Physical Oceanography, 46 (2). 635-661. https://doi.org/10.1175/JPO-D-14-0201.1 <https://doi.org/10.1175/JPO-D-14-0201.1> |
op_doi |
https://doi.org/10.1175/JPO-D-14-0201.1 |
container_title |
Journal of Physical Oceanography |
container_volume |
46 |
container_issue |
2 |
container_start_page |
635 |
op_container_end_page |
661 |
_version_ |
1766251520543686656 |