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Titel |
Natural variability and anthropogenic effects in a Central Mediterranean core |
VerfasserIn |
S. Alessio, G. Vivaldo, C. Taricco, M. Ghil |
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. 2 ; Nr. 8, no. 2 (2012-04-20), S.831-839 |
Datensatznummer |
250005487
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Publikation (Nr.) |
copernicus.org/cp-8-831-2012.pdf |
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Zusammenfassung |
We evaluate the contribution of natural variability to the modern decrease in
foraminiferal δ18O by relying on a 2200-yr-long, high-resolution
record of oxygen isotopic ratio from a Central Mediterranean sediment core.
Pre-industrial values are used to train and test two sets of algorithms that
are able to forecast the natural variability in δ18O over the last
150 yr. These algorithms are based on autoregressive models and neural
networks, respectively; they are applied separately to each of the
δ18O series' significant variability components, rather than to the
complete series. The separate components are extracted by singular-spectrum
analysis and have narrow-band spectral content, which reduces the forecast
error. By comparing the sum of the predicted low-frequency components to its actual
values during the Industrial Era, we deduce that the natural contribution to these
components of the modern δ18O variation decreased gradually, until it
reached roughly 40%, as early as the end of the 1970s. |
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