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| Titel |
δ18O water isotope in the iLOVECLIM model (version 1.0) – Part 3: A palaeo-perspective based on present-day data–model comparison for oxygen stable isotopes in carbonates |
| VerfasserIn |
T. Caley, D. M. Roche |
| 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 ; 6, no. 5 ; Nr. 6, no. 5 (2013-09-12), S.1505-1516 |
| Datensatznummer |
250084990
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| Publikation (Nr.) |
 copernicus.org/gmd-6-1505-2013.pdf |
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| Zusammenfassung |
| Oxygen stable isotopes (δ18O) are among the
most useful tools in palaeoclimatology/palaeoceanography. Simulation of oxygen
stable isotopes allows testing how the past variability of these isotopes in
water can be interpreted. By modelling the proxy directly in the model, the
results can also be directly compared with the data. Water isotopes have
been implemented in the global three-dimensional model of intermediate
complexity iLOVECLIM, allowing fully coupled
atmosphere–ocean simulations. In this study, we present the validation of
the model results for present-day climate against the global database for oxygen
stable isotopes in carbonates. The limitation of the model together with the
processes operating in the natural environment reveal the complexity of use
the continental calcite-δ18O signal of
speleothems for a global quantitative data–model comparison exercise. On the
contrary, the reconstructed surface ocean calcite-δ18O signal in iLOVECLIM does show a
very good agreement with the late Holocene database (foraminifers) at the global
and regional scales. Our results indicate that temperature and the isotopic
composition of the seawater are the main control on the fossil-δ18O
signal recorded in foraminifer shells when all
species are grouped together. Depth habitat, seasonality and other
ecological effects play a more significant role when individual species are
considered. We argue that a data–model comparison for surface ocean calcite
δ18O in past climates, such as the Last Glacial
Maximum (≈ 21 000 yr), could constitute an interesting tool
for mapping the potential shifts of the frontal systems and circulation
changes throughout time. Similarly, the potential changes in intermediate
oceanic circulation systems in the past could be documented by a data
(benthic foraminifers)-model comparison exercise whereas future
investigations are necessary in order to quantitatively compare the results
with data for the deep ocean. |
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