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| Titel |
Oxygen stable isotopes: data-model (iLOVECLIM) comparison for last glacial maximum climate |
| VerfasserIn |
Thibaut Caley, Didier Roche, Claire Waelbroeck, Elisabeth Michel |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250091801
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| Publikation (Nr.) |
 EGU/EGU2014-6112.pdf |
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| Zusammenfassung |
| Oxygen stable isotopes (δ18O) are among the most usual tools in paleoclimatology-paleoceanography. δ18O constitute an important tracer of the hydrological cycle from various components of the climatic system (ocean, atmosphere, ice sheets).
While being widely used proxy in climate archives from the different realms, processes that control the δ18O so recorded are various and complex. By using a model (iLOVECLIM) that is able to explicitly simulate the sensor (δ18O), results can be directly compared with data from climatic archives in the different realms.
We present a comparison between LGM simulated and measured oxygen isotopes. Our results indicate that iLOVECLIM reproduces well the main feature of the LGM climate in the atmospheric and oceanic components. The annual mean δ18O in precipitation shows more depleted values in the northern and southern high latitudes during the LGM. The model reproduces very well the spatial gradient observed in ice core records over the Greenland ice-sheet. We observe a general pattern toward more enriched values for continental calcite δ18O in the model at the LGM, in agreement with speleothem data. Our data-model comparison for ocean calcite δ18O allows investigating the large discrepancies with respect to glacial temperatures recorded by different microfossil proxies in the North Atlantic region. The results argue for a strong mean annual cooling between the LGM and present (>6°C).
Our simulation of the deep ocean suggests that changes in δ18Osw between the LGM and present are not spatially homogeneous, a fact that is supported by reconstructions derived from pore fluids in deep-sea sediments. |
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