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Titel |
Two case studies on the interaction of large-scale transport, mesoscale photochemistry, and boundary-layer processes on the lower tropospheric ozone dynamics in early spring |
VerfasserIn |
S. Brönnimann, F. C. Siegrist, W. Eugster, R. Cattin, C. Sidle, M. M. Hirschberg, D. Schneiter, S. Perego, H. Wanner |
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 ; 19, no. 4 ; Nr. 19, no. 4, S.469-486 |
Datensatznummer |
250014239
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Publikation (Nr.) |
copernicus.org/angeo-19-469-2001.pdf |
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Zusammenfassung |
The vertical distribution
of ozone in the lower troposphere over the Swiss Plateau is investigated in
detail for two episodes in early spring (February 1998 and March 1999). Profile
measurements of boundary-layer ozone performed during two field campaigns with a
tethered balloon sounding system and a kite are investigated using regular
aerological and ozone soundings from a nearby site, measurements from monitoring
stations at various altitudes, backward trajectories, and synoptic analyses of
meteorological fields. Additionally, the effect of in situ photochemistry
was estimated for one of the episodes employing the Metphomod Eulerian
photochemical model. Although the meteorological situations were completely
different, both cases had elevated layers with high ozone concentrations, which
is not untypical for late winter and early spring. In the February episode, the
highest ozone concentrations of 55 to 60 ppb, which were found at around 1100 m
asl, were partly advected from Southern France, but a considerable contribution
of in situ photochemistry is also predicted by the model. Below
that elevation, the local chemical sinks and surface deposition probably
overcompensated chemical production, and the vertical ozone distribution was
governed by boundary-layer dynamics. In the March episode, the results suggest
that ozone-rich air parcels, probably of stratospheric or upper tropospheric
origin, were advected aloft the boundary layer on the Swiss Plateau.
Key words. Atmospheric composition
and structure (pollution – urban and regional; troposphere – composition
and chemistry) – Meteorology and atmospheric dynamics (mesoscale
meteorology) |
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