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| Titel |
Tritium records to trace stratospheric moisture inputs in Antarctica along
with stable water isotopes and other tracers |
| VerfasserIn |
Elise Fourré, Amaëlle Landais, Alexandre Cauquoin, Philippe Jean-baptiste, Jean-Robert Petit |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250143791
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| Publikation (Nr.) |
 EGU/EGU2017-7545.pdf |
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| Zusammenfassung |
| Tritium is one of the very few proxies which can document the stratospheric-tropospheric
exchange. In fact natural tritium (3H) is mainly produced in the stratosphere by spallation and
rapidly enters the water cycle in the form of tritiated water molecules HTO. Due
to the high content of H2O in the troposphere compared to the stratosphere, the
present-day tritium content of the stratosphere is 105 times the tropospheric one.
HTO concentration in precipitation can thus be related to stratospheric moisture
input.
Apart from being a key region for climate studies, the East Antarctica Plateau with its low
water pressure and precipitation is especially sensitive to stratospheric inputs enriched in
tritium. In turn, tritium concentrations in East Antarctica snow should ideally be used to
assess the dynamics of stratosphere - troposphere exchanges, but tritium data are very
sparse.
In this study, we present high resolution measurements of tritium concentration over the
last 50 years at the Vostok station from three different snow pits: this allows us to identify
similar cyclic interannual pattern despite stratigraphic noise. For one of the pits, stable
water isotopes including 17O-excess, sodium concentration, as well 10Be have been
measured on the very same samples [1,2]. As for tritium, variations in 10Be are
modulated by the production under the influence of solar activity and partly by the
stratospheric inputs, but once produced 10Be becomes attached to ambient aerosols
and are transported and deposited with them. At Vostok, a possible link between
17O-excess and stratospheric moisture inputs variability has also been suggested
[2].
We explore the correlations between these different tracers to confirm the link with
stratospheric moisture inputs and to investigate the mechanisms at play in relation with the
climatic conditions. In this aim, confrontation with modeling outputs [3] from the LMDZ
Atmospheric General Circulation Model enhanced with both stable water isotopes and tritium
is very helpful and also allows a comparison of different daily atmospheric profiles
corresponding to various patterns in precipitation in terms of amounts and 18O and 3H
contents.
The combined use of tritium and stable water isotopes could help to decipher the winters
associated with frequent arrivals of warm air from the coast from winters associated with
more local moisture inputs.
[1] : Baroni et al., 2011, GCA, 75, 22, 7132-7145
[2] : Winkler et al., 2013, PNAS, 110, 44, 17674-17679
[3] : Cauquoin et al., 2016, JGR Atm, 121, 21, 12612-12629 |
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