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| Titel |
Multiscale monsoon variability during the last two climatic cycles revealed by spectral signals in Chinese loess and speleothem records |
| VerfasserIn |
Y. Li, N. Su, L. Liang, L. Ma, Y. Yan, Y. Sun |
| 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 ; 11, no. 8 ; Nr. 11, no. 8 (2015-08-25), S.1067-1075 |
| Datensatznummer |
250117388
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| Publikation (Nr.) |
 copernicus.org/cp-11-1067-2015.pdf |
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| Zusammenfassung |
| The East Asian Monsoon (EAM) exhibits a significant variability on timescales
ranging from tectonic to centennial as inferred from loess, speleothem and
marine records. However, the relative contributions and plausible driving
forces of the monsoon variability at different timescales remain
controversial. Here, we spectrally explore time series of loess grain size
and speleothem δ18O records and decompose the two proxies into
intrinsic components using the empirical mode decomposition method. Spectral
results of these two proxies display clear glacial and orbital periodicities
corresponding to ice volume and solar cycles, and evident millennial signals
which are in pace with Heinrich rhythm and Dansgaard–Oeschger (DO) cycles.
Five intrinsic components are parsed out from loess grain size and six
intrinsic components from speleothem δ18O records. Combined signals
are correlated further with possible driving factors including the ice
volume, insolation and North Atlantic cooling from a linear point of view.
The relative contributions of components differ significantly between loess
grain size and speleothem δ18O records. Coexistence of glacial and
orbital components in the loess grain size implies that both ice volume and
insolation have distinctive impacts on the winter monsoon variability, in
contrast to the predominant precessional impact on the speleothem
δ18O variability. Moreover, the millennial components are evident
in loess grain size and speleothem δ18O records with variances of
13 and 17 %, respectively. A comparison of the millennial-scale signals
of these two proxies reveals that abrupt changes in the winter and summer
monsoons over the last 260 kyr share common features and similar driving
forces linked to high-latitude Northern Hemisphere climate. |
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