Transport and storage of anthropogenic C in the North Atlantic Subpolar Ocean

<p>The North Atlantic Ocean is a major sink region for atmospheric CO<sub>2</sub> and contributes to the storage of anthropogenic carbon (Cant). While there is general agreement that the intensity of the meridional overturning circulation (MOC) modulates uptake, transport and st...

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Main Authors: V. Racapé, P. Zunino, H. Mercier, P. Lherminier, L. Bopp, F. F. Pérèz, M. Gehlen
Format: Article
Language:English
Published: Copernicus Publications 2018-07-01
Series:Biogeosciences
Online Access:https://www.biogeosciences.net/15/4661/2018/bg-15-4661-2018.pdf
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author V. Racapé
V. Racapé
P. Zunino
H. Mercier
P. Lherminier
L. Bopp
L. Bopp
F. F. Pérèz
M. Gehlen
author_facet V. Racapé
V. Racapé
P. Zunino
H. Mercier
P. Lherminier
L. Bopp
L. Bopp
F. F. Pérèz
M. Gehlen
author_sort V. Racapé
collection DOAJ
description <p>The North Atlantic Ocean is a major sink region for atmospheric CO<sub>2</sub> and contributes to the storage of anthropogenic carbon (Cant). While there is general agreement that the intensity of the meridional overturning circulation (MOC) modulates uptake, transport and storage of Cant in the North Atlantic Subpolar Ocean, processes controlling their recent variability and evolution over the 21st century remain uncertain. This study investigates the relationship between transport, air–sea flux and storage rate of Cant in the North Atlantic Subpolar Ocean over the past 53 years. Its relies on the combined analysis of a multiannual in situ data set and outputs from a global biogeochemical ocean general circulation model (NEMO–PISCES) at 1∕2° spatial resolution forced by an atmospheric reanalysis. Despite an underestimation of Cant transport and an overestimation of anthropogenic air–sea CO<sub>2</sub> flux in the model, the interannual variability of the regional Cant storage rate and its driving processes were well simulated by the model. Analysis of the multi-decadal simulation revealed that the MOC intensity variability was the major driver of the Cant transport variability at 25 and 36°&thinsp;N, but not at OVIDE. At the subpolar OVIDE section, the interannual variability of Cant transport was controlled by the accumulation of Cant in the MOC upper limb. At multi-decadal timescales, long-term changes in the North Atlantic storage rate of Cant were driven by the increase in air–sea fluxes of anthropogenic CO<sub>2</sub>. North Atlantic Central Water played a key role for storing Cant in the upper layer of the subtropical region and for supplying Cant to Intermediate Water and North Atlantic Deep Water. The transfer of Cant from surface to deep waters occurred mainly north of the OVIDE section. Most of the Cant transferred to the deep ocean was stored in the subpolar region, while the remainder was exported to the subtropical gyre within the lower MOC.</p>
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spelling doaj.art-31b5620a30264c24b395fc5b162e307c2022-12-21T19:03:56ZengCopernicus PublicationsBiogeosciences1726-41701726-41892018-07-01154661468210.5194/bg-15-4661-2018Transport and storage of anthropogenic C in the North Atlantic Subpolar OceanV. Racapé0V. Racapé1P. Zunino2H. Mercier3P. Lherminier4L. Bopp5L. Bopp6F. F. Pérèz7M. Gehlen8LSCE/IPSL, Laboratoire des Sciences du Climat et de l'environnement, CEA-CNRS-UVSQ, Orme des Merisiers, Bât. 712, CEA/Saclay, 91190 Gif-sur-Yvette, CEDEX, FranceIFREMER, Laboratoire d'Océanographie Physique et Spatiale, UMR 6523, CNRS-IFREMER-IRD-UBO, Plouzané, FranceCNRS, Laboratoire d'Océanographie Physique et Spatiale, UMR 6523, CNRS-IFREMER-IRD-UBO, Plouzané, FranceCNRS, Laboratoire d'Océanographie Physique et Spatiale, UMR 6523, CNRS-IFREMER-IRD-UBO, Plouzané, FranceIFREMER, Laboratoire d'Océanographie Physique et Spatiale, UMR 6523, CNRS-IFREMER-IRD-UBO, Plouzané, FranceLSCE/IPSL, Laboratoire des Sciences du Climat et de l'environnement, CEA-CNRS-UVSQ, Orme des Merisiers, Bât. 712, CEA/Saclay, 91190 Gif-sur-Yvette, CEDEX, FranceDépartement de Géosciences, Ecole Normale Supérieure, 24 rue Lhomond, 75005 Paris, FranceInstituto de Investigaciones Marinas, CSIC, Eduardo Cabello 6, 36208 Vigo, SpainLSCE/IPSL, Laboratoire des Sciences du Climat et de l'environnement, CEA-CNRS-UVSQ, Orme des Merisiers, Bât. 712, CEA/Saclay, 91190 Gif-sur-Yvette, CEDEX, France<p>The North Atlantic Ocean is a major sink region for atmospheric CO<sub>2</sub> and contributes to the storage of anthropogenic carbon (Cant). While there is general agreement that the intensity of the meridional overturning circulation (MOC) modulates uptake, transport and storage of Cant in the North Atlantic Subpolar Ocean, processes controlling their recent variability and evolution over the 21st century remain uncertain. This study investigates the relationship between transport, air–sea flux and storage rate of Cant in the North Atlantic Subpolar Ocean over the past 53 years. Its relies on the combined analysis of a multiannual in situ data set and outputs from a global biogeochemical ocean general circulation model (NEMO–PISCES) at 1∕2° spatial resolution forced by an atmospheric reanalysis. Despite an underestimation of Cant transport and an overestimation of anthropogenic air–sea CO<sub>2</sub> flux in the model, the interannual variability of the regional Cant storage rate and its driving processes were well simulated by the model. Analysis of the multi-decadal simulation revealed that the MOC intensity variability was the major driver of the Cant transport variability at 25 and 36°&thinsp;N, but not at OVIDE. At the subpolar OVIDE section, the interannual variability of Cant transport was controlled by the accumulation of Cant in the MOC upper limb. At multi-decadal timescales, long-term changes in the North Atlantic storage rate of Cant were driven by the increase in air–sea fluxes of anthropogenic CO<sub>2</sub>. North Atlantic Central Water played a key role for storing Cant in the upper layer of the subtropical region and for supplying Cant to Intermediate Water and North Atlantic Deep Water. The transfer of Cant from surface to deep waters occurred mainly north of the OVIDE section. Most of the Cant transferred to the deep ocean was stored in the subpolar region, while the remainder was exported to the subtropical gyre within the lower MOC.</p>https://www.biogeosciences.net/15/4661/2018/bg-15-4661-2018.pdf
spellingShingle V. Racapé
V. Racapé
P. Zunino
H. Mercier
P. Lherminier
L. Bopp
L. Bopp
F. F. Pérèz
M. Gehlen
Transport and storage of anthropogenic C in the North Atlantic Subpolar Ocean
Biogeosciences
title Transport and storage of anthropogenic C in the North Atlantic Subpolar Ocean
title_full Transport and storage of anthropogenic C in the North Atlantic Subpolar Ocean
title_fullStr Transport and storage of anthropogenic C in the North Atlantic Subpolar Ocean
title_full_unstemmed Transport and storage of anthropogenic C in the North Atlantic Subpolar Ocean
title_short Transport and storage of anthropogenic C in the North Atlantic Subpolar Ocean
title_sort transport and storage of anthropogenic c in the north atlantic subpolar ocean
url https://www.biogeosciences.net/15/4661/2018/bg-15-4661-2018.pdf
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