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Titel |
Dansgaard–Oeschger events: bifurcation points in the climate system |
VerfasserIn |
A. A. Cimatoribus, S. S. Drijfhout, V. Livina, G. Schrier |
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 ; 9, no. 1 ; Nr. 9, no. 1 (2013-02-06), S.323-333 |
Datensatznummer |
250017440
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Publikation (Nr.) |
copernicus.org/cp-9-323-2013.pdf |
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Zusammenfassung |
Dansgaard–Oeschger events are a prominent mode of variability in the records
of the last glacial cycle. Various prototype models have been proposed to
explain these rapid climate fluctuations, and no agreement has emerged on
which may be the more correct for describing the palaeoclimatic signal. In
this work, we assess the bimodality of the system, reconstructing the topology
of the multi-dimensional attractor over which the climate system evolves. We
use high-resolution ice core isotope data to investigate the statistical
properties of the climate fluctuations in the period before the onset of the
abrupt change. We show that Dansgaard–Oeschger events have weak early
warning signals if the ensemble of events is considered. We find that the
statistics are consistent with the switches between two different climate
equilibrium states in response to a changing external forcing (e.g. solar,
ice sheets), either forcing directly the transition or pacing it through
stochastic resonance. These findings are most consistent with a model that
associates Dansgaard–Oeschger with changing boundary conditions, and with
the presence of a bifurcation point. |
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