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| Titel |
Investigation of local meteorological events and their relationship with ozone and aerosols during an ESCOMPTE photochemical episode |
| VerfasserIn |
P. Augustin, H. Delbarre, F. Lohou, B. Campistron, V. Puygrenier, H. Cachier, T. Lombardo |
| 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 ; 24, no. 11 ; Nr. 24, no. 11 (2006-11-21), S.2809-2822 |
| Datensatznummer |
250015667
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| Publikation (Nr.) |
 copernicus.org/angeo-24-2809-2006.pdf |
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| Zusammenfassung |
The international ESCOMPTE campaign, which took place in summer 2001 in the
most highly polluted French region, was devoted to validate air pollution
prediction models. Surface and remote sensing instruments (Lidar, Radar and
Sodar) were deployed over the Marseille area, along the Mediterranean coast,
in order to investigate the fine structure of the sea-breeze circulation and
its relationship with the pollutant concentrations.
The geographical situation of the Marseille region combines a complex coastline
and relief which both lead to a peculiar behaviour of the sea-breeze circulation.
Several local sea breezes, perpendicular to the nearest coastline, settled
in during the morning. In the afternoons, when the thermal gradient between
the continental and marine surface grows up, a southerly or a westerly
sea breeze may dominate. Their respective importance is then a function of
time, space and altitude. Furthermore, an oscillation of the westerly
sea breeze with a period of about 3 h is also highlighted.
We show that these dynamical characteristics have profound influences on the
atmospheric boundary-layer (ABL) development and on pollutant
concentrations. In fact, the direction and intensity of the sea-breeze determine
the route and the transit time of the stable marine air flow over the
continental surface. Thus, the ABL depth may exhibit several collapses
correlated with the westerly sea-breeze pulsation. The ozone and aerosol
concentrations are also related to the dynamical features. In the suburbs
and parts of the city under pulsed sea breezes, a higher ABL depth and
higher ozone concentrations are observed. In the city centre, this
relationship between pulsed sea-breeze intensity and ozone concentration is
different, emphasising the importance of the transit time and also the
build-up of pollutants in the marine air mass along the route. Finally, the
variations of aerosol concentration are also described according to the breeze
direction. |
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