Mountains to climb: on the role of seamounts in upwelling of deep ocean waters
Ocean turbulent mixing exerts an important control on the rate and structure of the overturning circulation. Recent observational evidence suggests, however, that there could be a mismatch between the observed intensity of mixing integrated over basin or global scales, and the net mixing required to...
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ftarchimer:oai:archimer.ifremer.fr:84394 2023-05-15T18:25:33+02:00 Mountains to climb: on the role of seamounts in upwelling of deep ocean waters Mashayek, Ali Gula, Jonathan Baker, Lois Garabato, Alberto Naveira Cimoli, Laura Riley, James 2021-01 application/pdf https://archimer.ifremer.fr/doc/00732/84394/89406.pdf https://doi.org/10.21203/rs.3.rs-939198/v1 https://archimer.ifremer.fr/doc/00732/84394/ eng eng Research Square Platform LLC https://archimer.ifremer.fr/doc/00732/84394/89406.pdf doi:10.21203/rs.3.rs-939198/v1 https://archimer.ifremer.fr/doc/00732/84394/ info:eu-repo/semantics/openAccess restricted use Preprint (Research Square Platform LLC), 2021-01 , N. Version 1 , P. 15p. text Publication info:eu-repo/semantics/article 2021 ftarchimer https://doi.org/10.21203/rs.3.rs-939198/v1 2022-05-10T22:50:02Z Ocean turbulent mixing exerts an important control on the rate and structure of the overturning circulation. Recent observational evidence suggests, however, that there could be a mismatch between the observed intensity of mixing integrated over basin or global scales, and the net mixing required to sustain the overturning's deep upwelling limb. Here, we investigate the hitherto largely overlooked role of tens of thousands of seamounts in resolving this discrepancy. Dynamical theory indicates that seamounts may stir and mix deep waters by generating lee waves and topographic wake vortices. At low latitudes, this is enhanced by a layered vortex regime in the wakes. We consider three case studies (in the equatorial zone, Southern Ocean and Gulf Stream) that are predicted by theory to be representative of, respectively, a layered vortex, barotropic wake, and hybrid regimes, and corroborate theoretical scalings of mixing in each case with a realistic regional ocean model. We then apply such scalings to a global seamount dataset and an ocean climatology to show that seamount-generated mixing makes a leading-order contribution to the global upwelling of deep waters. Our work thus brings seamounts to the fore of the deep-ocean mixing problem, and urges observational, theoretical and modeling efforts toward incorporating the seamounts' mixing effects in conceptual and numerical models of the ocean circulation. Article in Journal/Newspaper Southern Ocean Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) Southern Ocean |
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Open Polar |
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Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) |
op_collection_id |
ftarchimer |
language |
English |
description |
Ocean turbulent mixing exerts an important control on the rate and structure of the overturning circulation. Recent observational evidence suggests, however, that there could be a mismatch between the observed intensity of mixing integrated over basin or global scales, and the net mixing required to sustain the overturning's deep upwelling limb. Here, we investigate the hitherto largely overlooked role of tens of thousands of seamounts in resolving this discrepancy. Dynamical theory indicates that seamounts may stir and mix deep waters by generating lee waves and topographic wake vortices. At low latitudes, this is enhanced by a layered vortex regime in the wakes. We consider three case studies (in the equatorial zone, Southern Ocean and Gulf Stream) that are predicted by theory to be representative of, respectively, a layered vortex, barotropic wake, and hybrid regimes, and corroborate theoretical scalings of mixing in each case with a realistic regional ocean model. We then apply such scalings to a global seamount dataset and an ocean climatology to show that seamount-generated mixing makes a leading-order contribution to the global upwelling of deep waters. Our work thus brings seamounts to the fore of the deep-ocean mixing problem, and urges observational, theoretical and modeling efforts toward incorporating the seamounts' mixing effects in conceptual and numerical models of the ocean circulation. |
format |
Article in Journal/Newspaper |
author |
Mashayek, Ali Gula, Jonathan Baker, Lois Garabato, Alberto Naveira Cimoli, Laura Riley, James |
spellingShingle |
Mashayek, Ali Gula, Jonathan Baker, Lois Garabato, Alberto Naveira Cimoli, Laura Riley, James Mountains to climb: on the role of seamounts in upwelling of deep ocean waters |
author_facet |
Mashayek, Ali Gula, Jonathan Baker, Lois Garabato, Alberto Naveira Cimoli, Laura Riley, James |
author_sort |
Mashayek, Ali |
title |
Mountains to climb: on the role of seamounts in upwelling of deep ocean waters |
title_short |
Mountains to climb: on the role of seamounts in upwelling of deep ocean waters |
title_full |
Mountains to climb: on the role of seamounts in upwelling of deep ocean waters |
title_fullStr |
Mountains to climb: on the role of seamounts in upwelling of deep ocean waters |
title_full_unstemmed |
Mountains to climb: on the role of seamounts in upwelling of deep ocean waters |
title_sort |
mountains to climb: on the role of seamounts in upwelling of deep ocean waters |
publisher |
Research Square Platform LLC |
publishDate |
2021 |
url |
https://archimer.ifremer.fr/doc/00732/84394/89406.pdf https://doi.org/10.21203/rs.3.rs-939198/v1 https://archimer.ifremer.fr/doc/00732/84394/ |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
Preprint (Research Square Platform LLC), 2021-01 , N. Version 1 , P. 15p. |
op_relation |
https://archimer.ifremer.fr/doc/00732/84394/89406.pdf doi:10.21203/rs.3.rs-939198/v1 https://archimer.ifremer.fr/doc/00732/84394/ |
op_rights |
info:eu-repo/semantics/openAccess restricted use |
op_doi |
https://doi.org/10.21203/rs.3.rs-939198/v1 |
_version_ |
1766207088401317888 |