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| Titel |
Implementation of counted layers for coherent ice core chronology |
| VerfasserIn |
B. Lemieux-Dudon, L. Bazin, A. Landais, H. Toye Mahamadou Kele, M. Guillevic, P. Kindler, F. Parrenin, P. Martinerie |
| 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. 6 ; Nr. 11, no. 6 (2015-06-25), S.959-978 |
| Datensatznummer |
250117324
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| Publikation (Nr.) |
 copernicus.org/cp-11-959-2015.pdf |
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| Zusammenfassung |
| A recent coherent chronology has been built for four Antarctic ice cores and the
NorthGRIP (NGRIP) Greenland ice core (Antarctic Ice Core Chronology 2012,
AICC2012) using a Bayesian approach for ice core dating (Datice). When
building the AICC2012 chronology, and in order to prevent any confusion with
official ice core chronology, the AICC2012 chronology for NGRIP was forced to
fit exactly the GICC05 chronology based on layer counting. However, such a
strong tuning did not satisfy the hypothesis of independence of background
parameters and observations for the NGRIP core, as required by Datice. We
present here the implementation in Datice of a new type of markers that is
better suited for constraints deduced from layer counting: the duration
constraints. Estimating the global error on chronology due to such markers is
not straightforward and implies some assumption on the correlation between
individual counting errors for each interval of duration. We validate this
new methodological implementation by conducting twin experiments and a
posteriori diagnostics on the NGRIP ice core. Several sensitivity tests on
marker sampling and correlation between counting errors were performed to
provide some guidelines when using such a method for future dating
experiments. Finally, using these markers for NGRIP in a five-core
dating exercise with Datice leads to new chronologies that do not differ by
more than 410 years from AICC2012 for Antarctic ice cores and 150 years from
GICC05 for NGRIP over the last 60 000 years. |
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