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| Titel |
Systematic study of the impact of fresh water fluxes on the glacial carbon cycle |
| VerfasserIn |
N. Bouttes, D. M. Roche, D. Paillard |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 8, no. 2 ; Nr. 8, no. 2 (2012-03-20), S.589-607 |
| Datensatznummer |
250005471
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| Publikation (Nr.) |
 copernicus.org/cp-8-589-2012.pdf |
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| Zusammenfassung |
During glacial periods, atmospheric CO2 concentration increases and
decreases by around 15 ppm. At the same time, the climate changes gradually
in Antarctica. Such climate changes can be simulated in models when the AMOC
(Atlantic Meridional Oceanic Circulation) is weakened by adding fresh water
to the North Atlantic. The impact on the carbon cycle is less
straightforward, and previous studies give opposite results. Because the
models and the fresh water fluxes were different in these studies, it
prevents any direct comparison and hinders finding whether the discrepancies
arise from using different models or different fresh water fluxes.
In this study we use the CLIMBER-2 coupled climate carbon model to explore
the impact of different fresh water fluxes. In both preindustrial and glacial
states, the addition of fresh water and the resulting slow-down of the AMOC
lead to an uptake of carbon by the ocean and a release by the terrestrial
biosphere. The duration, shape and amplitude of the fresh water flux all have
an impact on the change of atmospheric CO2 because they modulate the
change of the AMOC. The maximum CO2 change linearly depends on the time
integral of the AMOC change. The different duration, amplitude, and shape of
the fresh water flux cannot explain the opposite evolution of ocean and
vegetation carbon inventory in different models. The different CO2
evolution thus depends on the AMOC response to the addition of fresh water
and the resulting climatic change, which are both model dependent. In
CLIMBER-2, the rise of CO2 recorded in ice cores during abrupt events
can be simulated under glacial conditions, especially when the sinking of
brines in the Southern Ocean is taken into account. The addition of fresh
water in the Southern Hemisphere leads to a decline of CO2, contrary to
the addition of fresh water in the Northern Hemisphere. |
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