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Röckmann, Thomas, Kaiser, Jan 
ORCID: https://orcid.org/0000-0002-1553-4043, Crowley, John N., Brenninkmeijer, Carl A. M. and Crutzen, Paul J.
(2001)
The origin of the anomalous or “mass‐independent” oxygen isotope fractionation in tropospheric N2O.
Geophysical Research Letters, 28 (3).
pp. 503-506.
ISSN 0094-8276
Abstract
Analysis of the complete oxygen isotopic composition (16O, 17O, 18O) of tropospheric N2O from various northern hemispheric locations reveals a mass independent anomaly with a 17O excess of ?17O = 1.0±0.2‰ at d18O = 20.7±0.3‰. So far, the origin of this intriguing isotope signature has remained elusive. New laboratory experiments demonstrate that the fractionation during UV photolysis of N2O, which causes 15N and 18O enrichments in the stratosphere, is strictly mass dependent (?17O = 0). To explain the isotope anomaly in atmospheric N2O, we propose a chemical mechanism for heavy oxygen transfer from O3 to N2O. In a first step, the NOx-O3 photochemical interaction leads to the formation of NO2 with significant excess 17O. In a second step, the heavy oxygen anomaly is transferred to N2O via the reaction NO 2 + NH 2 ? N 2 O + H 2 O , as part of the gas phase degradation of ammonia. This small but significant N2O source is of the right magnitude to explain the tropospheric observations.
| Item Type: | Article |
|---|---|
| Faculty \ School: | Faculty of Science > School of Environmental Sciences University of East Anglia Research Groups/Centres > Theme - ClimateUEA |
| UEA Research Groups: | Faculty of Science > Research Groups > Centre for Ocean and Atmospheric Sciences Faculty of Science > Research Groups > Marine and Atmospheric Sciences (former - to 2017) Faculty of Science > Research Groups > Atmospheric Chemistry (former - to 2018) Faculty of Science > Research Groups > Climate, Ocean and Atmospheric Sciences (former - to 2017) |
| Depositing User: | Rosie Cullington |
| Date Deposited: | 15 Jun 2011 11:01 |
| Last Modified: | 20 Mar 2023 10:36 |
| URI: | https://ueaeprints.uea.ac.uk/id/eprint/32607 |
| DOI: | 10.1029/2000GL012295 |
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