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| Titel |
A nonlinear multi-proxy model based on manifold learning to reconstruct water temperature from high resolution trace element profiles in biogenic carbonates |
| VerfasserIn |
M. Bauwens, H. Ohlsson, K. Barbé, V. Beelaerts, J. Schoukens, F. Dehairs |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1991-959X
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| Digitales Dokument |
URL |
| Erschienen |
In: Geoscientific Model Development ; 3, no. 2 ; Nr. 3, no. 2 (2010-11-12), S.653-667 |
| Datensatznummer |
250000961
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| Publikation (Nr.) |
 copernicus.org/gmd-3-653-2010.pdf |
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| Zusammenfassung |
| A long standing problem in paleoceanography concerns the reconstruction of
water temperature from δ18O carbonate. It is problematic in the
case of freshwater influenced environments because the δ18O
isotopic composition of the ambient water (related to salinity) needs to be
known. In this paper we argue for the use of a nonlinear multi-proxy method
called Weight Determination by Manifold Regularization (WDMR) to develop a
temperature reconstruction model that is less sensitive to salinity
variations. The motivation for using this type of model is twofold: firstly,
observed nonlinear relations between specific proxies and water temperature
motivate the use of nonlinear models. Secondly, the use of multi-proxy models
enables salinity related variations of a given temperature proxy to be
explained by salinity-related information carried by a separate proxy. Our
findings confirm that Mg/Ca is a powerful paleothermometer and highlight that
reconstruction performance based on this proxy is improved significantly by
combining its information with the information for other trace elements in
multi-proxy models. Although the models presented here are black-box models
that do not use any prior knowledge about the proxies, the comparison of
model reconstruction performances based on different proxy combinations do
yield useful information about proxy characteristics. Using Mg/Ca, Sr/Ca,
Ba/Ca and Pb/Ca the WDMR model enables a temperature reconstruction with a
root mean squared error of ± 2.19 °C for a salinity range between
15 and 32. |
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