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| Titel |
The isotopic fingerprint of the pre-industrial and the anthropogenic N2O source |
| VerfasserIn |
T. Röckmann, J. Kaiser, C. A. M. Brenninkmeijer |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 3, no. 2 ; Nr. 3, no. 2 (2003-03-21), S.315-323 |
| Datensatznummer |
250000870
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| Publikation (Nr.) |
 copernicus.org/acp-3-315-2003.pdf |
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| Zusammenfassung |
| We have performed high-precision measurements of the
18O and position dependent 15N isotopic composition of
N2O from Antarctic firn air samples. By comparing these data to
simulations carried out with a firn air diffusion model, we have reconstructed the temporal
evolution of the N2O isotope signatures since pre-industrial times. The heavy isotope content
of atmospheric N2O is presently decreasing for all signatures at rates of about
-0.038 %o
yr -1 for 1d15N,
-0.046
%o yr
-1 for 2d
15N and -0.025 %o
yr -1 for d18O. The total decrease since pre-industrial
times is estimated to be about -1.8%o for
1d15N at both positions and
-2.2%o for
2d15N.
Isotope budget calculations using these trends and recent stratospheric measurements allow to
isotopically characterize the present and the pre-industrial global average
N2O source, as well as the additional N2O emissions that have caused the global
N2O increase since pre-industrial times. The increased fluxes from the depleted surface sources alone are insufficient
to explain the inferred temporal isotope changes. In addition, the global average
N2O source signature is calculated to be significantly depleted today relative to the pre-industrial value, in
agreement with recent indications from soil emission measurements. |
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