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| Titel |
The origin of the 1500-year climate cycles in Holocene North-Atlantic records |
| VerfasserIn |
M. Debret, V. Bout-Roumazeilles, F. Grousset, M. Desmet, J. F. McManus, N. Massei, D. Sebag, J.-R. Petit, Y. Copard, A. Trentesaux |
| 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 ; 3, no. 4 ; Nr. 3, no. 4 (2007-10-01), S.569-575 |
| Datensatznummer |
250001173
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| Publikation (Nr.) |
 copernicus.org/cp-3-569-2007.pdf |
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| Zusammenfassung |
| Since the first suggestion of 1500-year cycles in the advance and
retreat of glaciers (Denton and Karlen, 1973), many studies have uncovered
evidence of repeated climate oscillations of 2500, 1500, and 1000 years.
During last glacial period, natural climate cycles of 1500 years appear to
be persistent (Bond and Lotti, 1995) and remarkably regular (Mayewski et al.,
1997; Rahmstorf, 2003), yet the origin of this pacing during the Holocene
remains a mystery (Rahmstorf, 2003), making it one of the outstanding
puzzles of climate variability. Solar variability is often considered likely
to be responsible for such cyclicities, but the evidence for solar forcing
is difficult to evaluate within available data series due to the
shortcomings of conventional time-series analyses. However, the wavelets
analysis method is appropriate when considering non-stationary variability.
Here we show by the use of wavelets analysis that it is possible to
distinguish solar forcing of 1000- and 2500- year oscillations from
oceanic forcing of 1500-year cycles. Using this method, the relative
contribution of solar-related and ocean-related climate influences can be
distinguished throughout the 10 000 yr Holocene intervals since the last ice
age. These results reveal that the 1500-year climate cycles are linked with
the oceanic circulation and not with variations in solar output as
previously argued (Bond et al., 2001). In this light, previously studied
marine sediment (Bianchi and McCave, 1999; Chapman and Shackleton, 2000;
Giraudeau et al., 2000), ice core (O'Brien et al., 1995; Vonmoos et al., 2006)
and dust records (Jackson et al., 2005) can be seen to contain the evidence
of combined forcing mechanisms, whose relative influences varied during the
course of the Holocene. Circum-Atlantic climate records cannot be explained
exclusively by solar forcing, but require changes in ocean circulation, as
suggested previously (Broecker et al., 2001; McManus et al., 1999). |
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