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| Titel |
A subtropical Pacific view of the Mid-Pleistocene Transition |
| VerfasserIn |
Tom Russon, Mary Elliot, Aleksey Sadekov, Guy Cabioch, Thierry Corrège |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250046710
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| Zusammenfassung |
| The evolution of the low-latitude ocean/atmosphere system during the shift in dominant
modes of global glacial/interglacial climate variability associated with the Mid-Pleistocene
Transition (MPT) is not well constrained. Here, we present reconstructions of subtropical
southwest Pacific climate variability over the Pleistocene, as derived from coupled planktic
foraminiferal δ18O-Mg/Ca measurements taken from a southern Coral Sea sediment core. A
clear shift from ~40kyr to ~100kyr modes of reconstructed glacial/interglacial Sea Surface
Temperature (SST) variability is seen over the MPT and these fluctuations are shown
to have remained coherent with the orbital obliquity cycle across the transition.
The likely origin of this strong obliquity signal in subtropical southwest Pacific
SST is shown to be the southern high-latitudes and comparison with existing SST
reconstructions from the equatorial Pacific is consistent with the communication of
the signal occurring principally by greenhouse gas forcing. In contrast to the SST
reconstruction, regional hydrological cycle variability (based on the calculated
local component of δ18Osw change) shows only very limited coherence with the
obliquity cycle and a stronger relationship with the precession cycle. The decoupling of
the SST and hydrological cycle responses over the MPT allows constraints to be
placed on the role played by the coupled low-latitude ocean/atmosphere system in
the evolving sensitivity of global climate to orbital forcing across the transition. |
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