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Titel |
Parameterisation of the chemical effect of sprites in the middle atmosphere |
VerfasserIn |
C.-F. Enell, E. Arnone, T. Adachi, O. Chanrion, P. T. Verronen, A. Seppälä, T. Neubert, T. Ulich, E. Turunen, Y. Takahashi, R.-R. Hsu |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
0992-7689
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Digitales Dokument |
URL |
Erschienen |
In: Annales Geophysicae ; 26, no. 1 ; Nr. 26, no. 1 (2008-02-04), S.13-27 |
Datensatznummer |
250016000
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Publikation (Nr.) |
copernicus.org/angeo-26-13-2008.pdf |
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Zusammenfassung |
Transient luminous events, such as red sprites, occur in the middle
atmosphere in the electric field above thunderstorms. We here
address the question whether these processes may be a significant
source of odd nitrogen and affect ozone or other important trace
species. A well-established coupled ion-neutral chemical model has
been extended for this purpose and applied together with estimated
rates of ionisation, excitation and dissociation based on
spectroscopic ratios from ISUAL on FORMOSAT-2. This approach is used
to estimate the NOx and ozone changes for two type
cases.
The NOx enhancements are at most one order of magnitude in
the streamers, which means a production of at most 10 mol per
event, or (given a global rate of occurrence of three events per
minute) some 150–1500 kg per day. The present study
therefore indicates that sprites are insignificant as a global
source of NOx. Local effects on ozone are also negligible,
but the local enhancement of NOx may be significant, up to 5
times the minimum background at 70 km in extraordinary cases. |
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