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| Titel |
Polar-night O3, NO2 and NO3 distributions during sudden stratospheric warmings in 2003–2008 as seen by GOMOS/Envisat |
| VerfasserIn |
V. F. Sofieva, N. Kalakoski, P. T. Verronen, S.-M. Päivärinta, E. Kyrölä, L. Backman, J. Tamminen |
| 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 ; 12, no. 2 ; Nr. 12, no. 2 (2012-01-24), S.1051-1066 |
| Datensatznummer |
250010547
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| Publikation (Nr.) |
 copernicus.org/acp-12-1051-2012.pdf |
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| Zusammenfassung |
Sudden stratospheric warmings (SSW) are large-scale transient events, which
have a profound effect on the Northern Hemisphere stratospheric circulation
in winter. During the SSW events the temperature in stratosphere increases
by several tens of Kelvins and zonal winds decelerate or reverse in
direction. Changes in temperature and dynamics significantly affect the
chemical composition of the middle atmosphere.
In this paper, the response of the middle-atmosphere trace gases during
several sudden stratospheric warmings in 2003–2008 is investigated using
measurements from the GOMOS (Global Ozone Monitoring by Occultation of
Stars) instrument on board the Envisat satellite. We have analyzed spatial
and temporal changes of NO2 and NO3 in the stratosphere, and of
ozone in the whole middle atmosphere. To facilitate our analyses, we have
used the temperature profiles data from the MLS (Microwave Limb Sounder)
instrument on board the Aura satellite, as well as simulations by the
FinROSE chemistry-transport model and the Sodankylä Ion and Neutral
Chemistry model (SIC). NO3 observations in the polar winter
stratosphere during SSWs are reported for the first time.
Changes in chemical composition are found not to be restricted to the
stratosphere, but to extend to mesosphere and lower thermosphere. They often
exhibit a complicated structure, because the distribution of trace gases is
affected by changes in both chemistry and dynamics. The tertiary ozone
maximum in the mesosphere often disappears with the onset of SSW, probably
because of strong mixing processes. The strong horizontal mixing with
outside-vortex air is well observed also in NO2 data, especially in
cases of enhanced NO2 inside the polar vortex before SSW. Almost in all
of the considered events, ozone near the secondary maximum decreases with
onset of SSW. In both experimental data and FinROSE modelling, ozone changes
are positively correlated with temperature changes in the lower stratosphere
in the dynamically controlled region below ~35 km, and they are
negatively correlated with temperature in the upper stratosphere (altitudes
35–50 km), where chemical processes play a significant role. Large
enhancements of stratospheric NO3, which strongly correlate with
temperature enhancements, are observed for all SSWs, as expected by the
current understanding of temperature-dependence of NO3 concentrations
and simulations with the CTM. |
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