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| Menviel, L.; Mouchet, A.; Meissner, K. J.; Joos, F.; England, M. H.. |
| δ13CO2 measured in Antarctic ice cores provides constraints on oceanic and terrestrial carbon cycle processes linked with millennial-scale changes in atmospheric CO2. However, the interpretation of δ13CO2 is not straightforward. Using carbon isotope-enabled versions of the LOVECLIM and Bern3D models, we perform a set of sensitivity experiments in which the formation rates of North Atlantic Deep Water (NADW), North Pacific Deep Water (NPDW), Antarctic Bottom Water (AABW) and Antarctic Intermediate Water (AAIW) are varied. We study the impact of these circulation changes on atmospheric δ13CO2 as well as on the oceanic δ13C distribution. In general, we find that the formation rates of AABW, NADW, NPDW and AAIW are negatively correlated with changes in δ13CO2:... |
| Tipo: Text |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00293/40406/38965.pdf |
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| Huiskamp, W. N.; Meissner, K. J.. |
| The 'Mystery Interval' (17.5-14.5 ka BP) is characterized by a large decline in atmospheric Delta C-14 synchronous with an increase in atmospheric CO2. The most widely accepted hypothesis to explain these observed shifts involves the existence of an isolated 'old' ocean carbon reservoir that was subsequently ventilated. Here we use the UVic Earth System Climate Model to locate a potential carbon rich and Delta C-14 depleted water mass under 17.5 ka BP boundary conditions. We then investigate two mechanisms for the potential ventilation of such a reservoir, namely the weakening of the North Atlantic Meridional Overturning due to iceberg calving and latitudinal shifts in Southern Hemisphere Westerlies (SHW) due to southern hemispheric warming. We find that... |
| Tipo: Text |
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| Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00265/37602/36904.pdf |
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| Menviel, L.; England, M. H.; Meissner, K. J.; Mouchet, A.; Yu, J.. |
| Paleoproxy records indicate that a marked weakening of the Atlantic Meridional Overturning Circulation (AMOC) during Heinrich events was often accompanied by a notable atmospheric CO2 increase. However, previous modeling studies display conflicting atmospheric CO2 responses to an AMOC shutdown. Here we use model simulations combined with paleoproxy records to show that depending on the deep and bottom water transport in the Northern and Southern Pacific Ocean during an AMOC weakening, the ocean can act either as a sink or a source of carbon. Results from idealized meltwater experiments as well as from a transient experiment covering Heinrich stadial 4 suggest that a shutdown of the AMOC during Heinrich stadials 4 (HS4) and 1 (HS1) led to an enhancement of... |
| Tipo: Text |
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| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00291/40227/38679.pdf |
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