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| Titel |
Daily ozone cycle in the stratosphere: global, regional and seasonal behaviour modelled with the Whole Atmosphere Community Climate Model |
| VerfasserIn |
A. Schanz, K. Hocke, N. Kämpfer |
| 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 ; 14, no. 14 ; Nr. 14, no. 14 (2014-07-30), S.7645-7663 |
| Datensatznummer |
250118913
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| Publikation (Nr.) |
 copernicus.org/acp-14-7645-2014.pdf |
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| Zusammenfassung |
| The Whole Atmosphere Community Climate Model (WACCM) is utilised to study the daily ozone cycle
and underlying photochemical and dynamical processes. The analysis is focused on the daily ozone
cycle in the middle stratosphere at 5 hPa where satellite-based trend estimates of
stratospheric ozone are most biased by diurnal sampling effects and drifting satellite orbits. The
simulated ozone cycle shows a minimum after sunrise and a maximum in the late afternoon. Further,
a seasonal variation of the daily ozone cycle in the stratosphere was found. Depending on season
and latitude, the peak-to-valley difference of the daily ozone cycle varies mostly between
3 and 5% (0.4 ppmv) with respect to the midnight ozone volume mixing ratio. The maximal
variation of 15% (0.8 ppmv) is found at the polar circle in summer. The global
pattern of the strength of the daily ozone cycle is mainly governed by the solar zenith angle and
the sunshine duration. In addition, we find synoptic-scale variations in the strength of the daily
ozone cycle. These variations are often anti-correlated to regional temperature anomalies and are
due to the temperature dependence of the rate coefficients k2 and k3 of the Chapman cycle
reactions. Further, the NOx catalytic cycle counteracts the accumulation of ozone
during daytime and leads to an anti-correlation between anomalies in NOx and the strength
of the daily ozone cycle. Similarly, ozone recombines with atomic oxygen which leads to an
anti-correlation between anomalies in ozone abundance and the strength of the daily ozone
cycle. At higher latitudes, an increase of the westerly (easterly) wind cause a decrease
(increase) in the sunshine duration of an air parcel leading to a weaker (stronger) daily ozone
cycle. |
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