Glacial ice sheet extent effects on modeled tidal mixing and the global overturning circulation
At present, tides supply approximately half (1 TW) of the energy necessary to sustain the global deep meridional overturning circulation (MOC) through diapycnal mixing. During the Last Glacial Maximum (19,000‐26,500 years BP; LGM) tidal dissipation in the open ocean may have strongly increased due t...
Published in: | Paleoceanography and Paleoclimatology |
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Online Access: | https://research.bangor.ac.uk/portal/en/researchoutputs/glacial-ice-sheet-extent-effects-on-modeled-tidal-mixing-and-the-global-overturning-circulation(11ed3ca2-28ff-466a-a816-fa0c45960667).html https://doi.org/10.1029/2019PA003644 https://research.bangor.ac.uk/ws/files/24693943/2019PA003644.pdf |
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ftuwalesbangcris:oai:research.bangor.ac.uk:publications/11ed3ca2-28ff-466a-a816-fa0c45960667 2023-05-15T13:47:18+02:00 Glacial ice sheet extent effects on modeled tidal mixing and the global overturning circulation Wilmes, Sophie-Berenice Schmittner, Andreas Green, Mattias 2019-08 application/pdf https://research.bangor.ac.uk/portal/en/researchoutputs/glacial-ice-sheet-extent-effects-on-modeled-tidal-mixing-and-the-global-overturning-circulation(11ed3ca2-28ff-466a-a816-fa0c45960667).html https://doi.org/10.1029/2019PA003644 https://research.bangor.ac.uk/ws/files/24693943/2019PA003644.pdf eng eng info:eu-repo/semantics/openAccess Wilmes , S-B , Schmittner , A & Green , M 2019 , ' Glacial ice sheet extent effects on modeled tidal mixing and the global overturning circulation ' , Paleoceanography , vol. 34 , no. 8 , pp. 1437-1454 . https://doi.org/10.1029/2019PA003644 article 2019 ftuwalesbangcris https://doi.org/10.1029/2019PA003644 2021-12-26T12:06:34Z At present, tides supply approximately half (1 TW) of the energy necessary to sustain the global deep meridional overturning circulation (MOC) through diapycnal mixing. During the Last Glacial Maximum (19,000‐26,500 years BP; LGM) tidal dissipation in the open ocean may have strongly increased due to the 120‐130 m global mean sea‐level drop and changes in ocean basin shape. However, few investigations into LGM climate and ocean circulation consider LGM tidal mixing changes. Here, using an intermediate complexity climate model we present a detailed investigation on how changes in tidal dissipation would affect the global MOC. Present‐day (PD) and LGM tidal constituents M2, S2, K1 and O1 are simulated using a tide model, and accounting for LGM bathymetric. The tide model results suggest that the LGM energy supply to the internal wave field was 1.8‐3 times larger than at present and highly sensitive to Antarctic and Laurentide ice sheet extent. Including realistic LGM tide forcing in the LGM climate simulations leads to large increases in Atlantic diapycnal diffusivities, and strengthens (by 14‐4% at 32°S) and deepens the Atlantic MOC.Present‐day (PD) and LGM tidal constituents M2, S2, K1 and O1 are simulated using a tide model, and accounting for LGM bathymetric. The tide model results suggest that the LGM energy supply to the internal wave field was 1.8‐3 times larger than at present and highly sensitive to Antarctic and Laurentide ice sheet extent. Including realistic LGM tide forcing in the LGM climate simulations leads to large increases in Atlantic diapycnal diffusivities, and strengthens (by 14‐4% at 32°S) and deepens the Atlantic MOC. Increased input of tidal energy leads to a greater draw‐down of North Atlantic Deep Water and mixing with Antarctic Bottom Water altering Atlantic temperature and salinity distributions. Our results imply that changes in tidal dissipation need be accounted for in paleo‐climate simulation setup as they can lead to large differences in ocean mixing, the global MOC, and presumably also ocean carbon and other biogeochemical cycles Article in Journal/Newspaper Antarc* Antarctic Ice Sheet North Atlantic Deep Water North Atlantic Bangor University: Research Portal Antarctic Paleoceanography and Paleoclimatology 34 8 1437 1454 |
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Open Polar |
collection |
Bangor University: Research Portal |
op_collection_id |
ftuwalesbangcris |
language |
English |
description |
At present, tides supply approximately half (1 TW) of the energy necessary to sustain the global deep meridional overturning circulation (MOC) through diapycnal mixing. During the Last Glacial Maximum (19,000‐26,500 years BP; LGM) tidal dissipation in the open ocean may have strongly increased due to the 120‐130 m global mean sea‐level drop and changes in ocean basin shape. However, few investigations into LGM climate and ocean circulation consider LGM tidal mixing changes. Here, using an intermediate complexity climate model we present a detailed investigation on how changes in tidal dissipation would affect the global MOC. Present‐day (PD) and LGM tidal constituents M2, S2, K1 and O1 are simulated using a tide model, and accounting for LGM bathymetric. The tide model results suggest that the LGM energy supply to the internal wave field was 1.8‐3 times larger than at present and highly sensitive to Antarctic and Laurentide ice sheet extent. Including realistic LGM tide forcing in the LGM climate simulations leads to large increases in Atlantic diapycnal diffusivities, and strengthens (by 14‐4% at 32°S) and deepens the Atlantic MOC.Present‐day (PD) and LGM tidal constituents M2, S2, K1 and O1 are simulated using a tide model, and accounting for LGM bathymetric. The tide model results suggest that the LGM energy supply to the internal wave field was 1.8‐3 times larger than at present and highly sensitive to Antarctic and Laurentide ice sheet extent. Including realistic LGM tide forcing in the LGM climate simulations leads to large increases in Atlantic diapycnal diffusivities, and strengthens (by 14‐4% at 32°S) and deepens the Atlantic MOC. Increased input of tidal energy leads to a greater draw‐down of North Atlantic Deep Water and mixing with Antarctic Bottom Water altering Atlantic temperature and salinity distributions. Our results imply that changes in tidal dissipation need be accounted for in paleo‐climate simulation setup as they can lead to large differences in ocean mixing, the global MOC, and presumably also ocean carbon and other biogeochemical cycles |
format |
Article in Journal/Newspaper |
author |
Wilmes, Sophie-Berenice Schmittner, Andreas Green, Mattias |
spellingShingle |
Wilmes, Sophie-Berenice Schmittner, Andreas Green, Mattias Glacial ice sheet extent effects on modeled tidal mixing and the global overturning circulation |
author_facet |
Wilmes, Sophie-Berenice Schmittner, Andreas Green, Mattias |
author_sort |
Wilmes, Sophie-Berenice |
title |
Glacial ice sheet extent effects on modeled tidal mixing and the global overturning circulation |
title_short |
Glacial ice sheet extent effects on modeled tidal mixing and the global overturning circulation |
title_full |
Glacial ice sheet extent effects on modeled tidal mixing and the global overturning circulation |
title_fullStr |
Glacial ice sheet extent effects on modeled tidal mixing and the global overturning circulation |
title_full_unstemmed |
Glacial ice sheet extent effects on modeled tidal mixing and the global overturning circulation |
title_sort |
glacial ice sheet extent effects on modeled tidal mixing and the global overturning circulation |
publishDate |
2019 |
url |
https://research.bangor.ac.uk/portal/en/researchoutputs/glacial-ice-sheet-extent-effects-on-modeled-tidal-mixing-and-the-global-overturning-circulation(11ed3ca2-28ff-466a-a816-fa0c45960667).html https://doi.org/10.1029/2019PA003644 https://research.bangor.ac.uk/ws/files/24693943/2019PA003644.pdf |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic Ice Sheet North Atlantic Deep Water North Atlantic |
genre_facet |
Antarc* Antarctic Ice Sheet North Atlantic Deep Water North Atlantic |
op_source |
Wilmes , S-B , Schmittner , A & Green , M 2019 , ' Glacial ice sheet extent effects on modeled tidal mixing and the global overturning circulation ' , Paleoceanography , vol. 34 , no. 8 , pp. 1437-1454 . https://doi.org/10.1029/2019PA003644 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1029/2019PA003644 |
container_title |
Paleoceanography and Paleoclimatology |
container_volume |
34 |
container_issue |
8 |
container_start_page |
1437 |
op_container_end_page |
1454 |
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1766246870472982528 |