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| Siani, Giuseppe; Michel, Elisabeth; De Pol-holz, Ricardo; Devries, Tim; Lamy, Frank; Carel, Melanie; Isguder, Gulay; Dewilde, Fabien; Lourantou, Anna. |
| The Southern Ocean plays a prominent role in the Earth's climate and carbon cycle. Changes in the Southern Ocean circulation may have regulated the release of CO2 to the atmosphere from a deep-ocean reservoir during the last deglaciation. However, the path and exact timing of this deglacial CO2 release are still under debate. Here we present measurements of deglacial surface reservoir C-14 age changes in the eastern Pacific sector of the Southern Ocean, obtained by C-14 dating of tephra deposited over the marine and terrestrial regions. These results, along with records of foraminifera benthic-planktic C-14 age and delta C-13 difference, provide evidence for three periods of enhanced upwelling in the Southern Ocean during the last deglaciation, supporting... |
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| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00263/37472/36804.pdf |
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| Devries, Tim; Le Quere, Corinne; Andrews, Oliver; Berthet, Sarah; Hauck, Judith; Ilyina, Tatiana; Landschuetzer, Peter; Lenton, Andrew; Lima, Ivan D.; Nowicki, Michael; Schwinger, Jorg; Seferian, Roland. |
| Measurements show large decadal variability in the rate of CO2 accumulation in the atmosphere that is not driven by CO2 emissions. The decade of the 1990s experienced enhanced carbon accumulation in the atmosphere relative to emissions, while in the 2000s, the atmospheric growth rate slowed, even though emissions grew rapidly. These variations are driven by natural sources and sinks of CO2 due to the ocean and the terrestrial biosphere. In this study, we compare three independent methods for estimating oceanic CO2 uptake and find that the ocean carbon sink could be responsible for up to 40% of the observed decadal variability in atmospheric CO2 accumulation. Data-based estimates of the ocean carbon sink from pCO(2) mapping methods and decadal ocean inverse... |
| Tipo: Text |
Palavras-chave: Carbon dioxide; Ocean carbon sink; Terrestrial carbon sink; Climate variability; Carbon budget. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00675/78728/80983.pdf |
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| Devries, Tim; Primeau, Francois. |
| Existing methods for inferring the ventilation age of water masses in the ocean using radiocarbon data neglect the effects of diffusive mixing. in the presence of varying atmospheric Delta(14)C, this neglect produces spurious time dependence in the estimated ventilation ages. To correct this deficiency we propose a new method for estimating the ventilation age from sediment core radiocarbon data. The new method is formulated in terms of parameterized age distributions that account for the effects of advective and diffusive transport in the ocean. When applied to simulated radiocarbon data from an OGCM, the method is able to closely reproduce the modeled ventilation age, whereas other methods are not. We also applied the method to sediment-core radiocarbon... |
| Tipo: Text |
Palavras-chave: Ocean Drilling Program; Site 887; Ventilation age; Radiocarbon; Transit-time distribution; Glacial-interglacial. |
| Ano: 2010 |
URL: https://archimer.ifremer.fr/doc/00231/34197/32870.pdf |
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