Sea-air CO2 fluxes in the Southern Ocean for the period 1990-2009
The Southern Ocean (44-75 degrees S) plays a critical role in the global carbon cycle, yet remains one of the most poorly sampled ocean regions. Different approaches have been used to estimate sea-air CO2 fluxes in this region: synthesis of surface ocean observations, ocean biogeochemical models, an...
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Online Access: | https://archimer.ifremer.fr/doc/00253/36409/34949.pdf https://doi.org/10.5194/bg-10-4037-2013 https://archimer.ifremer.fr/doc/00253/36409/ |
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ftarchimer:oai:archimer.ifremer.fr:36409 2023-05-15T18:24:51+02:00 Sea-air CO2 fluxes in the Southern Ocean for the period 1990-2009 Lenton, A. Tilbrook, B. Law, R. M. Bakker, D. Doney, S. C. Gruber, N. Ishii, M. Hoppema, M. Lovenduski, N. S. Matear, R. J. Mcneil, B. I. Metzl, N. Mikaloff Fletcher, S. E. Monteiro, P. M. S. Roedenbeck, C. Sweeney, C. Takahashi, T. 2013 application/pdf https://archimer.ifremer.fr/doc/00253/36409/34949.pdf https://doi.org/10.5194/bg-10-4037-2013 https://archimer.ifremer.fr/doc/00253/36409/ eng eng Copernicus Gesellschaft Mbh info:eu-repo/grantAgreement/EC/FP7/264879/EU//CARBOCHANGE https://archimer.ifremer.fr/doc/00253/36409/34949.pdf doi:10.5194/bg-10-4037-2013 https://archimer.ifremer.fr/doc/00253/36409/ Author(s) 2013. CC Attribution 3.0 License. info:eu-repo/semantics/openAccess restricted use CC-BY Biogeosciences (1726-4170) (Copernicus Gesellschaft Mbh), 2013 , Vol. 10 , N. 6 , P. 4037-4054 text Publication info:eu-repo/semantics/article 2013 ftarchimer https://doi.org/10.5194/bg-10-4037-2013 2021-09-23T20:25:56Z The Southern Ocean (44-75 degrees S) plays a critical role in the global carbon cycle, yet remains one of the most poorly sampled ocean regions. Different approaches have been used to estimate sea-air CO2 fluxes in this region: synthesis of surface ocean observations, ocean biogeochemical models, and atmospheric and ocean inversions. As part of the RECCAP (REgional Carbon Cycle Assessment and Processes) project, we combine these different approaches to quantify and assess the magnitude and variability in Southern Ocean sea-air CO2 fluxes between 1990-2009. Using all models and inversions (26), the integrated median annual sea-air CO2 flux of -0.42+/-0.07 Pg C yr(-1) for the 44-75 degrees S region, is consistent with the -0.27+/-0.13 Pg C yr(-1) calculated using surface observations. The circumpolar region south of 58 degrees S has a small net annual flux (model and inversion median: -0.04+/-0.07 Pg C yr(-1) and observations: +0.04+/-0.02 Pg C yr(-1)), with most of the net annual flux located in the 44 to 58 degrees S circumpolar band (model and inversion median: -0.36+/-0.09 Pg C yr(-1) and observations: -0.35+/-0.09 Pg C yr(-1)). Seasonally, in the 44-58 degrees S region, the median of 5 ocean biogeochemical models captures the observed sea-air CO2 flux seasonal cycle, while the median of 11 atmospheric inversions shows little seasonal change in the net flux. South of 58 degrees S, neither atmospheric inversions nor ocean biogeochemical models reproduce the phase and amplitude of the observed seasonal sea-air CO2 flux, particularly in the Austral Winter. Importantly, no individual atmospheric inversion or ocean biogeochemical model is capable of reproducing both the observed annual mean uptake and the observed seasonal cycle. This raises concerns about projecting future changes in Southern Ocean CO2 fluxes. The median interannual variability from atmospheric inversions and ocean biogeochemical models is substantial in the Southern Ocean; up to 25% of the annual mean flux, with 25% of this interannual variability attributed to the region south of 58 degrees S. Resolving long-term trends is difficult due to the large interannual variability and short time frame (1990-2009) of this study; this is particularly evident from the large spread in trends from inversions and ocean biogeochemical models. Nevertheless, in the period 1990-2009 ocean biogeochemical models do show increasing oceanic uptake consistent with the expected increase of -0.05 Pg C yr(-1) decade(-1). In contrast, atmospheric inversions suggest little change in the strength of the CO2 sink broadly consistent with the results of Le Quere et al. (2007). Article in Journal/Newspaper Southern Ocean Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) Austral Southern Ocean Biogeosciences 10 6 4037 4054 |
institution |
Open Polar |
collection |
Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) |
op_collection_id |
ftarchimer |
language |
English |
description |
The Southern Ocean (44-75 degrees S) plays a critical role in the global carbon cycle, yet remains one of the most poorly sampled ocean regions. Different approaches have been used to estimate sea-air CO2 fluxes in this region: synthesis of surface ocean observations, ocean biogeochemical models, and atmospheric and ocean inversions. As part of the RECCAP (REgional Carbon Cycle Assessment and Processes) project, we combine these different approaches to quantify and assess the magnitude and variability in Southern Ocean sea-air CO2 fluxes between 1990-2009. Using all models and inversions (26), the integrated median annual sea-air CO2 flux of -0.42+/-0.07 Pg C yr(-1) for the 44-75 degrees S region, is consistent with the -0.27+/-0.13 Pg C yr(-1) calculated using surface observations. The circumpolar region south of 58 degrees S has a small net annual flux (model and inversion median: -0.04+/-0.07 Pg C yr(-1) and observations: +0.04+/-0.02 Pg C yr(-1)), with most of the net annual flux located in the 44 to 58 degrees S circumpolar band (model and inversion median: -0.36+/-0.09 Pg C yr(-1) and observations: -0.35+/-0.09 Pg C yr(-1)). Seasonally, in the 44-58 degrees S region, the median of 5 ocean biogeochemical models captures the observed sea-air CO2 flux seasonal cycle, while the median of 11 atmospheric inversions shows little seasonal change in the net flux. South of 58 degrees S, neither atmospheric inversions nor ocean biogeochemical models reproduce the phase and amplitude of the observed seasonal sea-air CO2 flux, particularly in the Austral Winter. Importantly, no individual atmospheric inversion or ocean biogeochemical model is capable of reproducing both the observed annual mean uptake and the observed seasonal cycle. This raises concerns about projecting future changes in Southern Ocean CO2 fluxes. The median interannual variability from atmospheric inversions and ocean biogeochemical models is substantial in the Southern Ocean; up to 25% of the annual mean flux, with 25% of this interannual variability attributed to the region south of 58 degrees S. Resolving long-term trends is difficult due to the large interannual variability and short time frame (1990-2009) of this study; this is particularly evident from the large spread in trends from inversions and ocean biogeochemical models. Nevertheless, in the period 1990-2009 ocean biogeochemical models do show increasing oceanic uptake consistent with the expected increase of -0.05 Pg C yr(-1) decade(-1). In contrast, atmospheric inversions suggest little change in the strength of the CO2 sink broadly consistent with the results of Le Quere et al. (2007). |
format |
Article in Journal/Newspaper |
author |
Lenton, A. Tilbrook, B. Law, R. M. Bakker, D. Doney, S. C. Gruber, N. Ishii, M. Hoppema, M. Lovenduski, N. S. Matear, R. J. Mcneil, B. I. Metzl, N. Mikaloff Fletcher, S. E. Monteiro, P. M. S. Roedenbeck, C. Sweeney, C. Takahashi, T. |
spellingShingle |
Lenton, A. Tilbrook, B. Law, R. M. Bakker, D. Doney, S. C. Gruber, N. Ishii, M. Hoppema, M. Lovenduski, N. S. Matear, R. J. Mcneil, B. I. Metzl, N. Mikaloff Fletcher, S. E. Monteiro, P. M. S. Roedenbeck, C. Sweeney, C. Takahashi, T. Sea-air CO2 fluxes in the Southern Ocean for the period 1990-2009 |
author_facet |
Lenton, A. Tilbrook, B. Law, R. M. Bakker, D. Doney, S. C. Gruber, N. Ishii, M. Hoppema, M. Lovenduski, N. S. Matear, R. J. Mcneil, B. I. Metzl, N. Mikaloff Fletcher, S. E. Monteiro, P. M. S. Roedenbeck, C. Sweeney, C. Takahashi, T. |
author_sort |
Lenton, A. |
title |
Sea-air CO2 fluxes in the Southern Ocean for the period 1990-2009 |
title_short |
Sea-air CO2 fluxes in the Southern Ocean for the period 1990-2009 |
title_full |
Sea-air CO2 fluxes in the Southern Ocean for the period 1990-2009 |
title_fullStr |
Sea-air CO2 fluxes in the Southern Ocean for the period 1990-2009 |
title_full_unstemmed |
Sea-air CO2 fluxes in the Southern Ocean for the period 1990-2009 |
title_sort |
sea-air co2 fluxes in the southern ocean for the period 1990-2009 |
publisher |
Copernicus Gesellschaft Mbh |
publishDate |
2013 |
url |
https://archimer.ifremer.fr/doc/00253/36409/34949.pdf https://doi.org/10.5194/bg-10-4037-2013 https://archimer.ifremer.fr/doc/00253/36409/ |
geographic |
Austral Southern Ocean |
geographic_facet |
Austral Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
Biogeosciences (1726-4170) (Copernicus Gesellschaft Mbh), 2013 , Vol. 10 , N. 6 , P. 4037-4054 |
op_relation |
info:eu-repo/grantAgreement/EC/FP7/264879/EU//CARBOCHANGE https://archimer.ifremer.fr/doc/00253/36409/34949.pdf doi:10.5194/bg-10-4037-2013 https://archimer.ifremer.fr/doc/00253/36409/ |
op_rights |
Author(s) 2013. CC Attribution 3.0 License. info:eu-repo/semantics/openAccess restricted use |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.5194/bg-10-4037-2013 |
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Biogeosciences |
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10 |
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6 |
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4037 |
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4054 |
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1766205816817319936 |