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| Titel |
An estimation of the 18O / 16O ratio of UT/LMS ozone based on artefact CO in air sampled during CARIBIC flights |
| VerfasserIn |
S. Gromov, 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 ; 15, no. 4 ; Nr. 15, no. 4 (2015-02-24), S.1901-1912 |
| Datensatznummer |
250119450
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| Publikation (Nr.) |
 copernicus.org/acp-15-1901-2015.pdf |
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| Zusammenfassung |
| An issue of O3-driven artefact production of O3 in the upper
troposphere/lowermost stratosphere (UT/LMS) air analysed in the CARIBIC-1
project is being discussed. By confronting the CO mixing and isotope ratios
obtained from different analytical instrumentation, we (i) reject
natural/artificial sampling and mixing effects as possible culprits of the
problem, (ii) ascertain the chemical nature and quantify the strength of the
contamination, and (iii) demonstrate successful application of the isotope
mass-balance calculations for inferring the isotope composition of the
contamination source. The δ18O values of the latter indicate that the
oxygen is very likely being inherited from O3. The δ13C values
hint at reactions of trace amounts of organics with stratospheric O3
that could have yielded the artificial CO. While the exact contamination
mechanism is not known, it is clear that the issue pertains only to the
earlier (first) phase of the CARIBIC (Civil Aircraft for the Regular Investigation of the
atmosphere Based on an Instrument Container) project. Finally, estimated UT/LMS ozone
δ18O values are lower than those observed in the stratosphere
within the same temperature range, suggesting that higher pressures
(240–270 hPa) imply lower isotope fractionation controlling the local
δ18O(O3) value. |
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