A weaker Atlantic Meridional Overturning Circulation at the Last Glacial Maximum led to a greater deep ocean carbon content
While paleoproxy records and modelling studies consistently suggest that North Atlantic Deep Water (NADW) was shallower at the Last Glacial Maximum (LGM) than during pre-industrial times, its strength is still subject to debate partly due to different signals across the North Atlantic. Here, using a...
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ftccsdartic:oai:HAL:hal-03541566v1 2023-12-17T10:21:33+01:00 A weaker Atlantic Meridional Overturning Circulation at the Last Glacial Maximum led to a greater deep ocean carbon content Menviel, Laurie Spence, Paul Skinner, Luke Kazuyo, Tachikawa Friedrich, Tobias Missiaen, Lise Yu, Jimin Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE) Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE) 2022-01-24 https://hal.science/hal-03541566 https://doi.org/10.5194/egusphere-egu2020-2920 en eng HAL CCSD info:eu-repo/semantics/altIdentifier/doi/10.5194/egusphere-egu2020-2920 hal-03541566 https://hal.science/hal-03541566 doi:10.5194/egusphere-egu2020-2920 https://hal.science/hal-03541566 2022 [SDU.STU]Sciences of the Universe [physics]/Earth Sciences info:eu-repo/semantics/preprint Preprints, Working Papers, . 2022 ftccsdartic https://doi.org/10.5194/egusphere-egu2020-2920 2023-11-19T00:17:13Z While paleoproxy records and modelling studies consistently suggest that North Atlantic Deep Water (NADW) was shallower at the Last Glacial Maximum (LGM) than during pre-industrial times, its strength is still subject to debate partly due to different signals across the North Atlantic. Here, using a series of LGM experiments performed with a carbon isotopes enabled Earth system model, we show that proxy records are consistent with a shallower and weaker NADW. A significant equatorward advance of sea-ice over the Labrador Sea and the Nordic Seas shifts the NADW convection sites to the south of the Norwegian Sea. While the deep western boundary current in the Northwest Atlantic weakens with NADW, a change in density gradients strengthens the deep southward flow in the Northeast Atlantic. A shoaling and weakening of NADW further allow penetration of Antarctic Bottom Water in the North Atlantic despite its transport being reduced. This resultant globally weaker oceanic circulation leads to an increase in deep ocean carbon of ~500 GtC, thus significantly contributing to the lower LGM atmospheric CO 2 concentration. Report Antarc* Antarctic Labrador Sea NADW Nordic Seas North Atlantic Deep Water North Atlantic Northeast Atlantic Northwest Atlantic Norwegian Sea Sea ice Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Antarctic Norwegian Sea |
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Open Polar |
collection |
Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
op_collection_id |
ftccsdartic |
language |
English |
topic |
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
spellingShingle |
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences Menviel, Laurie Spence, Paul Skinner, Luke Kazuyo, Tachikawa Friedrich, Tobias Missiaen, Lise Yu, Jimin A weaker Atlantic Meridional Overturning Circulation at the Last Glacial Maximum led to a greater deep ocean carbon content |
topic_facet |
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
description |
While paleoproxy records and modelling studies consistently suggest that North Atlantic Deep Water (NADW) was shallower at the Last Glacial Maximum (LGM) than during pre-industrial times, its strength is still subject to debate partly due to different signals across the North Atlantic. Here, using a series of LGM experiments performed with a carbon isotopes enabled Earth system model, we show that proxy records are consistent with a shallower and weaker NADW. A significant equatorward advance of sea-ice over the Labrador Sea and the Nordic Seas shifts the NADW convection sites to the south of the Norwegian Sea. While the deep western boundary current in the Northwest Atlantic weakens with NADW, a change in density gradients strengthens the deep southward flow in the Northeast Atlantic. A shoaling and weakening of NADW further allow penetration of Antarctic Bottom Water in the North Atlantic despite its transport being reduced. This resultant globally weaker oceanic circulation leads to an increase in deep ocean carbon of ~500 GtC, thus significantly contributing to the lower LGM atmospheric CO 2 concentration. |
author2 |
Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE) Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE) |
format |
Report |
author |
Menviel, Laurie Spence, Paul Skinner, Luke Kazuyo, Tachikawa Friedrich, Tobias Missiaen, Lise Yu, Jimin |
author_facet |
Menviel, Laurie Spence, Paul Skinner, Luke Kazuyo, Tachikawa Friedrich, Tobias Missiaen, Lise Yu, Jimin |
author_sort |
Menviel, Laurie |
title |
A weaker Atlantic Meridional Overturning Circulation at the Last Glacial Maximum led to a greater deep ocean carbon content |
title_short |
A weaker Atlantic Meridional Overturning Circulation at the Last Glacial Maximum led to a greater deep ocean carbon content |
title_full |
A weaker Atlantic Meridional Overturning Circulation at the Last Glacial Maximum led to a greater deep ocean carbon content |
title_fullStr |
A weaker Atlantic Meridional Overturning Circulation at the Last Glacial Maximum led to a greater deep ocean carbon content |
title_full_unstemmed |
A weaker Atlantic Meridional Overturning Circulation at the Last Glacial Maximum led to a greater deep ocean carbon content |
title_sort |
weaker atlantic meridional overturning circulation at the last glacial maximum led to a greater deep ocean carbon content |
publisher |
HAL CCSD |
publishDate |
2022 |
url |
https://hal.science/hal-03541566 https://doi.org/10.5194/egusphere-egu2020-2920 |
geographic |
Antarctic Norwegian Sea |
geographic_facet |
Antarctic Norwegian Sea |
genre |
Antarc* Antarctic Labrador Sea NADW Nordic Seas North Atlantic Deep Water North Atlantic Northeast Atlantic Northwest Atlantic Norwegian Sea Sea ice |
genre_facet |
Antarc* Antarctic Labrador Sea NADW Nordic Seas North Atlantic Deep Water North Atlantic Northeast Atlantic Northwest Atlantic Norwegian Sea Sea ice |
op_source |
https://hal.science/hal-03541566 2022 |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.5194/egusphere-egu2020-2920 hal-03541566 https://hal.science/hal-03541566 doi:10.5194/egusphere-egu2020-2920 |
op_doi |
https://doi.org/10.5194/egusphere-egu2020-2920 |
_version_ |
1785535851484151808 |