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| Titel |
Can we predict the duration of an interglacial? |
| VerfasserIn |
P. C. Tzedakis, E. W. Wolff, L. C. Skinner, V. Brovkin, D. A. Hodell, J. F. McManus, D. Raynaud |
| 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. 5 ; Nr. 8, no. 5 (2012-09-24), S.1473-1485 |
| Datensatznummer |
250005836
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| Publikation (Nr.) |
 copernicus.org/cp-8-1473-2012.pdf |
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| Zusammenfassung |
| Differences in the duration of interglacials have long been apparent in
palaeoclimate records of the Late and Middle Pleistocene. However, a
systematic evaluation of such differences has been hampered by the lack of a
metric that can be applied consistently through time and by difficulties in
separating the local from the global component in various proxies. This, in
turn, means that a theoretical framework with predictive power for
interglacial duration has remained elusive. Here we propose that the
interval between the terminal oscillation of the bipolar seesaw and three
thousand years (kyr) before its first major reactivation provides an
estimate that approximates the length of the sea-level highstand, a measure
of interglacial duration. We apply this concept to interglacials of the last
800 kyr by using a recently-constructed record of interhemispheric
variability. The onset of interglacials occurs within 2 kyr of the boreal
summer insolation maximum/precession minimum and is consistent with the
canonical view of Milankovitch forcing pacing the broad timing of
interglacials. Glacial inception always takes place when obliquity is
decreasing and never after the obliquity minimum. The phasing of precession
and obliquity appears to influence the persistence of interglacial
conditions over one or two insolation peaks, leading to shorter (~ 13 kyr)
and longer (~ 28 kyr) interglacials. Glacial inception occurs
approximately 10 kyr after peak interglacial conditions in temperature and
CO2, representing a characteristic timescale of interglacial decline.
Second-order differences in duration may be a function of stochasticity in
the climate system, or small variations in background climate state and the
magnitude of feedbacks and mechanisms contributing to glacial inception, and
as such, difficult to predict. On the other hand, the broad duration of an
interglacial may be determined by the phasing of
astronomical parameters and the history of insolation, rather than the
instantaneous forcing strength at inception. |
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