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| Titel |
Lifetime and production rate of NOx in the upper stratosphere and lower mesosphere in the polar spring/summer after the solar proton event in October-November 2003 |
| VerfasserIn |
F. Friederich, T. Clarmann, B. Funke, H. Nieder, J. Orphal, M. Sinnhuber, G. P. Stiller, J. M. Wissing |
| 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 ; 13, no. 5 ; Nr. 13, no. 5 (2013-03-05), S.2531-2539 |
| Datensatznummer |
250018470
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| Publikation (Nr.) |
 copernicus.org/acp-13-2531-2013.pdf |
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| Zusammenfassung |
We present altitude-dependent lifetimes of NOx, determined with
MIPAS/ENVISAT (the Michelson Interferometer for Passive Atmospheric Sounding/the European
Environment Satellite), for the Southern polar region after the solar proton event in
October–November 2003. Between 50° S and 90° S and
decreasing in altitude they range from about two days at 64 km to about 20
days at 44 km. The lifetimes are controlled by transport, mixing and
photochemistry. We infer estimates of dynamical lifetimes by comparison of
the observed decay to photochemical lifetimes calculated with the SLIMCAT 3-D
Model. Photochemical loss contributes to the observed NOx depletion by
0.1% at 44 km, increasing with altitude to 45% at 64 km.
In addition, we show the correlation of modelled ionization rates and observed
NOx densities under consideration of the determined lifetimes of NOx, and
calculate altitude-dependent effective production rates of NOx due to
ionization. For that we compare ionization rates of the AIMOS data base with
the MIPAS measurements from 15 October–31 December 2003. We derive
effective NOx-production rates to be applied to the AIMOS ionization rates
which range from about 0.2 NOx-molecules per ion pair at 44 km to 0.7 NOx-molecules per ion pair at 62 km. These effective production rates are
considerably lower than predicted by box model simulations which could hint
at an overestimation of the modelled ionization rates. |
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