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| Titel |
First continuous measurements of water vapor isotopes on the Antarctic Plateau |
| VerfasserIn |
Francois Ritter, Hans Christian Steen-Larsen, Sepp Kipfstuhl, Anaïs Orsi, Melanie Behrens, Valérie Masson-Delmotte |
| 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 |
250094317
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| Publikation (Nr.) |
 EGU/EGU2014-9721.pdf |
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| Zusammenfassung |
| We present the first continuous surface water vapor isotopic observations of δ18O, δD and absolute humidity taken from Kohnen Station in Dronning Maud Land (75°00'S, 00°04'E, 2892 m.a.s.l) from December 2013 to January 2014. The measurements were performed by cavity ringdown laser spectroscopy using a LGR inc water vapor analyzer at three different levels at 0.2, 1.0 and 3.0 meter, with a temporal resolution of about 35 minutes for each height. Despite the very low water vapor concentration (400-2000 ppm), we are able to obtain a precision on the order of ~0.5‰ for δ18O and ~1.5‰ for δD through a robust calibration routine.
Our observations reveal a strong diurnal cycle in both the water vapor concentration and isotopic composition, associated with a significant humidity gradient inversion at night (up to ~10‰ in δ18O peak-to-peak and ~30‰ in d-excess peak-to-peak). We discuss the origin of this daily cycle in a katabatic dominated environment.
The corrected isotopes show a strong relationship with the absolute humidity consistent with classical Rayleigh distillation. We see a deviation from the linear local meteoric water line of δD vs δ18O for depleted values.
These unique observations will also allow us to test and improve the parameterization of snow-atmosphere interaction, which has important implications for the interpretation of ice-core records. |
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