Carbon isotopes and Pa / Th response to forced circulation changes: a model perspective
Understanding the ocean circulation changes associated with last glacial abrupt climate events is key to better assess climate variability and understand its different natural modes. Sedimentary Pa / Th, benthic δ 13 C and Δ 14 C are common proxies used to reconstruct past circulation flow rate and...
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ftcopernicus:oai:publications.copernicus.org:cpd75601 2023-05-15T17:24:23+02:00 Carbon isotopes and Pa / Th response to forced circulation changes: a model perspective Missiaen, Lise Bouttes, Nathaelle Roche, Didier M. Dutay, Jean-Claude Quiquet, Aurélien Waelbroeck, Claire Pichat, Sylvain Peterschmitt, Jean-Yves 2019-04-23 info:eu-repo/semantics/application/pdf https://doi.org/10.5194/cp-2019-45 https://www.clim-past-discuss.net/cp-2019-45/ eng eng info:eu-repo/grantAgreement/EC/FP7/339108 doi:10.5194/cp-2019-45 https://www.clim-past-discuss.net/cp-2019-45/ info:eu-repo/semantics/openAccess eISSN: 1814-9332 info:eu-repo/semantics/Text 2019 ftcopernicus https://doi.org/10.5194/cp-2019-45 2019-12-24T09:49:17Z Understanding the ocean circulation changes associated with last glacial abrupt climate events is key to better assess climate variability and understand its different natural modes. Sedimentary Pa / Th, benthic δ 13 C and Δ 14 C are common proxies used to reconstruct past circulation flow rate and ventilation. To overcome the limitations of each proxy taken separately, a better approach is to produce multi-proxy measurements on a single sediment core. Yet, different proxies can provide conflicting information about past ocean circulation. Thus, modelling them in a consistent physical framework has become necessary to assess the geographical pattern, the timing and sequence of the multi-proxy response to abrupt circulation changes. We have implemented a representation of the 231 Pa and 230 Th tracers into the model of intermediate complexity iLOVECLIM, which already included δ 13 C and Δ 14 C. We have further evaluated the response of these three ocean circulation proxies to a classical abrupt circulation reduction obtained by freshwater addition in the Nordic seas under preindustrial boundary conditions. Without a priori guess, the proxy response is shown to cluster in modes that resemble the modern Atlantic water masses. The clearest and most coherent response is obtained in the deep (> 2,000 m) Northwest Atlantic, where δ 13 C and Δ 14 C significantly decrease while Pa / Th increases. This is consistent with observational data across millennial scale events of the last glacial. Interestingly, while in marine records, except in rare instances, the phase relationship between these proxies remains unclear due to large dating uncertainties, in the model the bottom water carbon isotopes (δ 13 C and Δ 14 C) response lags the sedimentary Pa / Th response by a few hundred years. Other/Unknown Material Nordic Seas Northwest Atlantic Copernicus Publications: E-Journals |
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Open Polar |
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Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
Understanding the ocean circulation changes associated with last glacial abrupt climate events is key to better assess climate variability and understand its different natural modes. Sedimentary Pa / Th, benthic δ 13 C and Δ 14 C are common proxies used to reconstruct past circulation flow rate and ventilation. To overcome the limitations of each proxy taken separately, a better approach is to produce multi-proxy measurements on a single sediment core. Yet, different proxies can provide conflicting information about past ocean circulation. Thus, modelling them in a consistent physical framework has become necessary to assess the geographical pattern, the timing and sequence of the multi-proxy response to abrupt circulation changes. We have implemented a representation of the 231 Pa and 230 Th tracers into the model of intermediate complexity iLOVECLIM, which already included δ 13 C and Δ 14 C. We have further evaluated the response of these three ocean circulation proxies to a classical abrupt circulation reduction obtained by freshwater addition in the Nordic seas under preindustrial boundary conditions. Without a priori guess, the proxy response is shown to cluster in modes that resemble the modern Atlantic water masses. The clearest and most coherent response is obtained in the deep (> 2,000 m) Northwest Atlantic, where δ 13 C and Δ 14 C significantly decrease while Pa / Th increases. This is consistent with observational data across millennial scale events of the last glacial. Interestingly, while in marine records, except in rare instances, the phase relationship between these proxies remains unclear due to large dating uncertainties, in the model the bottom water carbon isotopes (δ 13 C and Δ 14 C) response lags the sedimentary Pa / Th response by a few hundred years. |
format |
Other/Unknown Material |
author |
Missiaen, Lise Bouttes, Nathaelle Roche, Didier M. Dutay, Jean-Claude Quiquet, Aurélien Waelbroeck, Claire Pichat, Sylvain Peterschmitt, Jean-Yves |
spellingShingle |
Missiaen, Lise Bouttes, Nathaelle Roche, Didier M. Dutay, Jean-Claude Quiquet, Aurélien Waelbroeck, Claire Pichat, Sylvain Peterschmitt, Jean-Yves Carbon isotopes and Pa / Th response to forced circulation changes: a model perspective |
author_facet |
Missiaen, Lise Bouttes, Nathaelle Roche, Didier M. Dutay, Jean-Claude Quiquet, Aurélien Waelbroeck, Claire Pichat, Sylvain Peterschmitt, Jean-Yves |
author_sort |
Missiaen, Lise |
title |
Carbon isotopes and Pa / Th response to forced circulation changes: a model perspective |
title_short |
Carbon isotopes and Pa / Th response to forced circulation changes: a model perspective |
title_full |
Carbon isotopes and Pa / Th response to forced circulation changes: a model perspective |
title_fullStr |
Carbon isotopes and Pa / Th response to forced circulation changes: a model perspective |
title_full_unstemmed |
Carbon isotopes and Pa / Th response to forced circulation changes: a model perspective |
title_sort |
carbon isotopes and pa / th response to forced circulation changes: a model perspective |
publishDate |
2019 |
url |
https://doi.org/10.5194/cp-2019-45 https://www.clim-past-discuss.net/cp-2019-45/ |
genre |
Nordic Seas Northwest Atlantic |
genre_facet |
Nordic Seas Northwest Atlantic |
op_source |
eISSN: 1814-9332 |
op_relation |
info:eu-repo/grantAgreement/EC/FP7/339108 doi:10.5194/cp-2019-45 https://www.clim-past-discuss.net/cp-2019-45/ |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/cp-2019-45 |
_version_ |
1766115365406900224 |