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| Titel |
Natural periodicities and Northern Hemisphere–Southern Hemisphere connection of fast temperature changes during the last glacial period: EPICA and NGRIP revisited |
| VerfasserIn |
T. Alberti, F. Lepreti, A. Vecchio, E. Bevacqua, V. Capparelli, V. Carbone |
| 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 ; 10, no. 5 ; Nr. 10, no. 5 (2014-09-19), S.1751-1762 |
| Datensatznummer |
250117053
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| Publikation (Nr.) |
 copernicus.org/cp-10-1751-2014.pdf |
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| Zusammenfassung |
| We investigate both the European Project for Ice Coring in Antarctica
Dronning Maud Land (EDML) and North Greenland Ice-Core Project (NGRIP) data
sets to study both the time evolution of the so-called Dansgaard–Oeschger
events and the dynamics at longer timescales during the last glacial period.
Empirical mode decomposition (EMD) is used to extract the proper modes of
both the data sets. It is shown that the time behavior at the typical
timescales of Dansgaard–Oeschger events is captured through signal
reconstructions obtained by summing five EMD modes for NGRIP and four EMD
modes for EDML. The reconstructions obtained by summing the successive modes
can be used to describe the climate evolution at longer timescales,
characterized by intervals in which Dansgaard–Oeschger events happen and
intervals when these are not observed. Using EMD signal reconstructions and a
simple model based on the one-dimensional Langevin equation, it is argued
that the occurrence of a Dansgaard–Oeschger event can be described as an
excitation of the climate system within the same state, while the longer
timescale behavior appears to be due to transitions between different climate
states. Finally, on the basis of a cross-correlation analysis performed on
EMD reconstructions, evidence that the Antarctic climate changes lead those
of Greenland by a lag of ≈ 3.05 kyr is presented. |
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