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| Titel |
A chemical fingerprint of surface UV in the 20th century firn record of nitrate stable isotopes at Dome C, East Antarctica |
| VerfasserIn |
M. M. Frey, J. Savarino, S. Morin, J. Erbland |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250026742
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| Zusammenfassung |
| Recent studies on atmospheric particulate nitrate (NO3-) demonstrated that the nitrogen and
triple oxygen stable isotopic composition of NO3- allows constraining atmospheric sources
and sinks, namely oxidation pathways of reactive nitrogen. However, the application of this
tool to past atmospheres using ice cores is complicated. Especially in the low accumulation
regions of East Antarctica significant post-depositional processing via UV-photolysis
and evaporation in the upper snow pack alters not only NO3- concentrations but
also its isotopic signature. Conversely, it is hypothesized here that the degree of
post-depositional fractionation allows to infer past atmospheric conditions at the
surface.
Nitrate 15N/14N and 18O/16O isotopic ratios were measured at Dome Concordia,
Antarctica 75.1-S, 123.3-E) in a 6m-snow pit extending 60 years back in time. A significant
anti-correlation observed between δ15N(NO3-) and δ18O(NO3-) (r=-0.75, p |
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