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| Titel |
Drake Passage, pCO2 and Antarctica Cenozoic glaciation |
| VerfasserIn |
S. Bonelli, Y. Donnadieu, G. Ramstein, C. Dumas |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250023286
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| Zusammenfassung |
| The Cenozoic glaciation of Antarctica marks the onset of a phase of the Earth’s history
characterized by the existence of large continental ice sheets. The long term trend of
decreasing atmospheric CO2 on the one hand, and tectonic activity leading to the opening and
deepening of the Drake Passage (DP) on the other, have been invoked as potential main
triggering mechanisms. Here we adopt an original approach based on a fully coupled
climate-cryosphere model to investigate the role of both forcing factors on Antarctica
glaciation and on global climate. Our results reveal that, although the rapid pCO2 decrease
plays a major role, the non-linear response of Antarctica hydrology to the DP opening is
fundamental to explain the large ice sheet build up for CO2concentration around three times
the pre-industrial atmospheric level (PAL), as recorded in δ18O data. Furthermore, it is only
in case of open DP that the AIS volume evolution vs pCO2 is characterized by an abrupt
transition. Indeed, for open DP simulations, the inception of the AIS follows a threshold
behaviour, consistent with the rapid shift recorded in δ18O data at the Eocene-Oligocene
boundary.
Keywords: Cenozoic Antarctic glaciation, climate system models, ice sheet models,
climate-cryosphere coupling, Drake Passage |
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