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| Titel |
Vertical profile of peroxyacetyl nitrate (PAN) from MIPAS-STR measurements over Brazil in February 2005 and its contribution to tropical UT NOy partitioning |
| VerfasserIn |
C. Keim, G. Y. Liu, C. E. Blom, H. Fischer, T. Gulde, M. Höpfner, C. Piesch, F. Ravegnani, A. Roiger, H. Schlager, N. Sitnikov |
| 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 ; 8, no. 16 ; Nr. 8, no. 16 (2008-08-26), S.4891-4902 |
| Datensatznummer |
250006340
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| Publikation (Nr.) |
 copernicus.org/acp-8-4891-2008.pdf |
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| Zusammenfassung |
We report on the retrieval of PAN (CH3C(O)OONO2) in the upper
tropical troposphere from limb measurements by the remote-sensor MIPAS-STR on
board the Russian high altitude research aircraft M55-Geophysica. The
measurements were performed close to Araçatuba, Brazil, on 17 February
2005. The retrieval was made in the spectral range 775–820 cm−1
where PAN exhibits its strongest feature but also more than 10 species
interfere. Especially trace gases such as CH3CCl3, CFC-113, CFC-11,
and CFC-22, emitting also in spectrally broad not-resolved branches, make the
processing of PAN prone to errors. Therefore, the selection of appropriate
spectral windows, the separate retrieval of several interfering species and
the careful handling of the water vapour profile are part of the study
presented.
The retrieved profile of PAN has a maximum of about 0.14 ppbv at 10 km
altitude, slightly larger than the lowest reported values
(<0.1 ppbv) and much lower than the highest reported in the
literature (0.65 ppbv). Besides the NOy constituents
measured by MIPAS-STR (HNO3, ClONO2, HO2NO2, PAN),
the in situ instruments aboard the Geophysica provide simultaneous
measurements of NO, NO2, and the sum NOy. Comparing
the sum of in-situ and remotely derived
NO+NO2+HNO3+ClONO2+HO2NO2+PAN with
total NOy a deficit of 30–40% (0.2–0.3 ppbv) in the troposphere
remains unexplained whereas the values fit well in the stratosphere. |
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