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| Titel |
Glacial CO2 cycle as a succession of key physical and biogeochemical processes |
| VerfasserIn |
V. Brovkin, A. Ganopolski, D. Archer, G. Munhoven |
| 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. 1 ; Nr. 8, no. 1 (2012-02-09), S.251-264 |
| Datensatznummer |
250005372
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| Publikation (Nr.) |
 copernicus.org/cp-8-251-2012.pdf |
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| Zusammenfassung |
| During glacial-interglacial cycles, atmospheric CO2 concentration
varied by about 100 ppmv in amplitude. While testing mechanisms that have led
to the low glacial CO2 level could be done in equilibrium model
experiments, an ultimate goal is to explain CO2 changes in transient
simulations through the complete glacial-interglacial cycle. The
computationally efficient Earth System model of intermediate complexity
CLIMBER-2 is used to simulate global biogeochemistry over the last glacial
cycle (126 kyr). The physical core of the model (atmosphere, ocean, land and
ice sheets) is driven by orbital changes and reconstructed radiative forcing
from greenhouses gases, ice, and aeolian dust. The carbon cycle model is
able to reproduce the main features of the CO2 changes: a 50 ppmv
CO2 drop during glacial inception, a minimum concentration at the last
glacial maximum 80 ppmv lower than the Holocene value, and an abrupt 60 ppmv
CO2 rise during the deglaciation. The model deep ocean δ13C
also resembles reconstructions from deep-sea cores. The main
drivers of atmospheric CO2 evolve in time: changes in sea surface
temperatures and in the volume of bottom water of southern origin control
atmospheric CO2 during the glacial inception and deglaciation; changes in carbonate chemistry and marine biology are dominant during the
first and second parts of the glacial cycle, respectively. These feedback
mechanisms could also significantly impact the ultimate climate response to
the anthropogenic perturbation. |
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