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| Titel |
Interhemispheric coupling, the West Antarctic Ice Sheet and warm Antarctic interglacials |
| VerfasserIn |
P. B. Holden, N. R. Edwards, E. W. Wolff, N. J. Lang, J. S. Singarayer, P. J. Valdes, T. F. Stocker |
| 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 ; 6, no. 4 ; Nr. 6, no. 4 (2010-07-16), S.431-443 |
| Datensatznummer |
250003652
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| Publikation (Nr.) |
 copernicus.org/cp-6-431-2010.pdf |
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| Zusammenfassung |
| Ice core evidence indicates that even though atmospheric CO2
concentrations did not exceed ~300 ppm at any point during the last
800 000 years, East Antarctica was at least ~3–4 °C warmer than
preindustrial (CO2~280 ppm) in each of the last four
interglacials. During the previous three interglacials, this anomalous
warming was short lived (~3000 years) and apparently occurred before
the completion of Northern Hemisphere deglaciation. Hereafter, we refer to
these periods as "Warmer than Present Transients" (WPTs). We present a
series of experiments to investigate the impact of deglacial meltwater on
the Atlantic Meridional Overturning Circulation (AMOC) and Antarctic
temperature. It is well known that a slowed AMOC would increase southern sea
surface temperature (SST) through the bipolar seesaw and observational data
suggests that the AMOC remained weak throughout the terminations preceding
WPTs, strengthening rapidly at a time which coincides closely with peak
Antarctic temperature. We present two 800 kyr transient simulations using
the Intermediate Complexity model GENIE-1 which demonstrate that meltwater
forcing generates transient southern warming that is consistent with the
timing of WPTs, but is not sufficient (in this single parameterisation) to
reproduce the magnitude of observed warmth. In order to investigate model
and boundary condition uncertainty, we present three ensembles of transient
GENIE-1 simulations across Termination II (135 000 to 124 000 BP) and three
snapshot HadCM3 simulations at 130 000 BP. Only with consideration of the
possible feedback of West Antarctic Ice Sheet (WAIS) retreat does it become
possible to simulate the magnitude of observed warming. |
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