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| Titel |
Spatial (data and model) and temporal variability of 17O-excess in East Antarctica |
| VerfasserIn |
Renato Winkler, Amaëlle Landais, Ryu Umuera, Cunde Xiao, Georg Hoffmann, Jean Jouzel, Maxwell Kelley, Kotaro Fukui |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250035894
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| Zusammenfassung |
| For many decades stable water isotopes (δD and δ18O) are used as tracers in earth’s
hydrological cycle in order to get information about climatic parameters such as
temperature and precipitation. In particular, δD and δ18O in ice cores permit to reconstruct
the polar temperature of the past. Improvements of the analytical devices made it
possible to measure also the δ17O of water with high precision. The combination of
δ18O and δ17O leads to the definition of the so called 17O-excess (ln(δ17O/1000
+1)-0.528ln(δ18O/1000+1)) by analogy with the d-excess (δD -8δ18O). It has been
suggested that 17O-excess in the ice cores is a more direct indicator of relative
humidity of the source region than d-excess and that the combination of the two
parameters is essential to reconstruct the past climatic conditions in the evaporative
regions.
Here we show new results for the spatial and temporal distribution of 17O-excess in East
Antarctica. We especially explore the isotopic composition of the surface snow in remote
regions of East Antarctica characterized by very low δ18O (between -60 and -55 permil).
Then, we present the record of 17O-excess over the last deglaciation (26 to 8 kyrs BP) in the
EPICA Dome C ice core. Interestingly, this 17O-excess record shows a more stable behavior
than the one at Vostok. Finally, we compare our results with the spatial variability of
17O-excess in precipitation obtained by the old version of the GISS GCM model. |
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