Sea–air CO<sub>2</sub> fluxes in the Southern Ocean for the period 1990–2009

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dc.contributor.authorLaufkötter, C
dc.contributor.authorHoppema, M
dc.contributor.authorLovenduski, N S
dc.contributor.authorMatear, R J
dc.contributor.authorMcNeil, B I
dc.contributor.authorMetzl, N
dc.contributor.authorMikaloff Fletcher, S E
dc.contributor.authorMonteiro, P M S
dc.contributor.authorRödenbeck, C
dc.contributor.authorSweeney, C
dc.contributor.authorTakahashi, T
dc.date.accessioned2021-10-08T06:20:15Z
dc.date.available2021-10-08T06:20:15Z
dc.date.issued2013
dc.description.abstractThe Southern Ocean (44-75° 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° S region, is consistent with the -0.27 ± 0.13 Pg C yr-1 calculated using surface observations. The circumpolar region south of 58° 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° 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° 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° 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° 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 Quéré et al. (2007).
dc.identifier.apacitationLaufkötter, C., Hoppema, M., Lovenduski, N. S., Matear, R. J., McNeil, B. I., Metzl, N., ... Takahashi, T. (2013). Sea–air CO<sub>2</sub> fluxes in the Southern Ocean for the period 1990–2009. <i>Biogeosciences</i>, 10(6), 4037 - 4054. http://hdl.handle.net/11427/34233en_ZA
dc.identifier.chicagocitationLaufkötter, C, M Hoppema, N S Lovenduski, R J Matear, B I McNeil, N Metzl, S E Mikaloff Fletcher, et al "Sea–air CO<sub>2</sub> fluxes in the Southern Ocean for the period 1990–2009." <i>Biogeosciences</i> 10, 6. (2013): 4037 - 4054. http://hdl.handle.net/11427/34233en_ZA
dc.identifier.citationLaufkötter, C., Hoppema, M., Lovenduski, N.S., Matear, R.J., McNeil, B.I., Metzl, N., Mikaloff Fletcher, S.E. & Monteiro, P.M.S. et al. 2013. Sea–air CO<sub>2</sub> fluxes in the Southern Ocean for the period 1990–2009. <i>Biogeosciences.</i> 10(6):4037 - 4054. http://hdl.handle.net/11427/34233en_ZA
dc.identifier.issn1726-4170
dc.identifier.issn1726-4189
dc.identifier.ris TY - Journal Article AU - Laufkötter, C AU - Hoppema, M AU - Lovenduski, N S AU - Matear, R J AU - McNeil, B I AU - Metzl, N AU - Mikaloff Fletcher, S E AU - Monteiro, P M S AU - Rödenbeck, C AU - Sweeney, C AU - Takahashi, T AB - The Southern Ocean (44-75° 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° S region, is consistent with the -0.27 ± 0.13 Pg C yr-1 calculated using surface observations. The circumpolar region south of 58° 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° 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° 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° 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° 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 Quéré et al. (2007). DA - 2013 DB - OpenUCT DP - University of Cape Town IS - 6 J1 - Biogeosciences LK - https://open.uct.ac.za PY - 2013 SM - 1726-4170 SM - 1726-4189 T1 - Sea–air CO<sub>2</sub> fluxes in the Southern Ocean for the period 1990–2009 TI - Sea–air CO<sub>2</sub> fluxes in the Southern Ocean for the period 1990–2009 UR - http://hdl.handle.net/11427/34233 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/34233
dc.identifier.vancouvercitationLaufkötter C, Hoppema M, Lovenduski NS, Matear RJ, McNeil BI, Metzl N, et al. Sea–air CO<sub>2</sub> fluxes in the Southern Ocean for the period 1990–2009. Biogeosciences. 2013;10(6):4037 - 4054. http://hdl.handle.net/11427/34233.en_ZA
dc.language.isoeng
dc.publisher.departmentDepartment of Oceanography
dc.publisher.facultyFaculty of Science
dc.sourceBiogeosciences
dc.source.journalissue6
dc.source.journalvolume10
dc.source.pagination4037 - 4054
dc.source.urihttps://dx.doi.org/10.5194/bg-10-4037-2013
dc.subject.otherBiology (General)
dc.subject.otherQ
dc.subject.otherDOAJ:Earth Sciences
dc.subject.otherDOAJ:Biology
dc.subject.otherDOAJ:Earth and Environmental Sciences
dc.subject.otherGeology
dc.subject.otherQE1-996.5
dc.subject.otherDOAJ:Biology and Life Sciences
dc.subject.otherQH301-705.5
dc.subject.otherScience
dc.titleSea–air CO<sub>2</sub> fluxes in the Southern Ocean for the period 1990–2009
dc.typeJournal Article
uct.type.publicationResearch
uct.type.resourceJournal Article
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