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| Titel |
Deglaciation records of ¹⁷O-excess in East Antarctica: reliable reconstruction of oceanic normalized relative humidity from coastal sites |
| VerfasserIn |
R. Winkler, A. Landais, H. Sodemann, L. Dümbgen, F. Prié, V. Masson-Delmotte, B. Stenni, J. Jouzel |
| 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. 1 ; Nr. 8, no. 1 (2012-01-03), S.1-16 |
| Datensatznummer |
250005357
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| Publikation (Nr.) |
 copernicus.org/cp-8-1-2012.pdf |
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| Zusammenfassung |
| We measured δ17O and δ18O in two Antarctic ice cores at
EPICA Dome C (EDC) and TALDICE (TD), respectively, and computed
17O-excess with respect to VSMOW. The comparison of our
17O-excess data with the previous record obtained at Vostok (Landais et al., 2008a) revealed differences up to 35 ppm in
17O-excess mean level and evolution for the three sites. Our
data show that the large increase depicted at Vostok (20 ppm) during the
last deglaciation is a regional and not a general pattern in the temporal
distribution of 17O-excess in East Antarctica. The EDC data
display an increase of 12 ppm, whereas the TD data show no significant
variation from the Last Glacial Maximum (LGM) to the Early Holocene (EH). A
Lagrangian moisture source diagnostic revealed very different source regions
for Vostok and EDC compared to TD. These findings combined with the results
of a sensitivity analysis, using a Rayleigh-type isotopic model, suggest that
normalized relative humidity (RHn) at the oceanic source region (OSR) is a determining
factor for the spatial differences of 17O-excess in East
Antarctica. However, 17O-excess in remote sites of continental
Antarctica (e.g. Vostok) may be highly sensitive to local effects. Hence, we
consider 17O-excess in coastal East Antarctic ice cores (TD) to
be more reliable as a proxy for RHn at the OSR. |
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