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| Titel |
Limitations of red noise in analysing Dansgaard-Oeschger events |
| VerfasserIn |
H. Braun, P. Ditlevsen, J. Kurths, M. Mudelsee |
| 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 ; 6, no. 1 ; Nr. 6, no. 1 (2010-02-19), S.85-92 |
| Datensatznummer |
250003328
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| Publikation (Nr.) |
 copernicus.org/cp-6-85-2010.pdf |
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| Zusammenfassung |
| During the last glacial period, climate records from the North Atlantic
region exhibit a pronounced spectral component corresponding to a period of
about 1470 years, which has attracted much attention. This spectral peak is
closely related to the recurrence pattern of Dansgaard-Oeschger (DO) events.
In previous studies a red noise random process, more precisely a first-order
autoregressive (AR1) process, was used to evaluate the statistical
significance of this peak, with a reported significance of more than 99%.
Here we use a simple mechanistic two-state model of DO events, which itself
was derived from a much more sophisticated ocean-atmosphere model of
intermediate complexity, to numerically evaluate the spectral properties of
random (i.e., solely noise-driven) events. This way we find that the power
spectral density of random DO events differs fundamentally from a simple red
noise random process. These results question the applicability of linear
spectral analysis for estimating the statistical significance of highly
non-linear processes such as DO events. More precisely, to enhance our
scientific understanding about the trigger of DO events, we must not
consider simple "straw men" as, for example, the AR1 random process, but
rather test against realistic alternative descriptions. |
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