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| Titel |
Antarctic warming driven by internal Southern Ocean deep convection oscillations |
| VerfasserIn |
Torge Martin, Joel B. Pedro, Eric J. Steig, Markus Jochum, Wonsun Park, Sune O. Rasmussen |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250127768
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| Publikation (Nr.) |
 EGU/EGU2016-7678.pdf |
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| Zusammenfassung |
| Simulations with the free-running, complex coupled Kiel Climate Model (KCM) show that
heat release associated with recurring Southern Ocean deep convection can drive
centennial-scale Antarctic temperature variations of 0.5–2.0 ∘C.
We propose a mechanism connecting the intrinsic ocean variability with Antarctic
warming that involves the following three steps:
Preconditioning: heat supplied by the lower branch of the Atlantic Meridional
Overturning Circulation (AMOC) accumulates at depth in the Southern Ocean,
trapped by the Weddell Gyre circulation;
Convection onset: wind and/or sea-ice changes tip the preconditioned, thermally
unstable system into the convective state;
Antarctic warming: fast sea-ice–albedo feedbacks (on annual to decadal
timescales) and slower Southern Ocean frontal and sea-surface temperature
adjustments to the convective heat release (on multi-decadal to centennial
timescales), drive an increase in atmospheric heat and moisture transport towards
Antarctica resulting in warming over the continent.
Further, we discuss the potential role of this mechanism to explain climate variability
observed in Antarctic ice-core records. |
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