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| Titel |
Effects on surface atmospheric photo-oxidants over Greece during the total solar eclipse event of 29 March 2006 |
| VerfasserIn |
P. Zanis, E. Katragkou, M. Kanakidou, B. E. Psiloglou, S. Karathanasis, M. Vrekoussis, E. Gerasopoulos, I. Lisaridis, K. Markakis, A. Poupkou, V. Amiridis, D. Melas, N. Mihalopoulos, C. Zerefos |
| 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 ; 7, no. 23 ; Nr. 7, no. 23 (2007-12-10), S.6061-6073 |
| Datensatznummer |
250005274
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| Publikation (Nr.) |
 copernicus.org/acp-7-6061-2007.pdf |
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| Zusammenfassung |
| This study investigates the effects of the total solar eclipse of 29 March
2006 on surface air-quality levels over Greece based on observations at a
number of sites in conjunction with chemical box modelling and 3-D
air-quality modelling. Emphasis is given on surface ozone and other
photooxidants at four Greek sites Kastelorizo, Finokalia (Crete), Pallini
(Athens) and Thessaloniki, which are located at gradually increasing
distances from the path of the eclipse totality and are characterized by
different air pollution levels. The eclipse offered the opportunity to test
our understanding of air pollution build-up and the response of the
gas-phase chemistry of photo-oxidants during a photolytical perturbation
using both a photochemical box model and a regional air-quality offline
model based on the modeling system WRF/CAMx. At the relatively unpolluted
sites of Kastelorizo and Finokalia no clear signal of the solar eclipse on
surface O3, NO2 and NO concentrations can be deduced from the
observations while there is no correlation of observed O3, NO2 and
NO with observed global radiation. The box and regional model simulations
for the two relatively unpolluted sites indicate that the calculated changes
in net ozone production rates between eclipse and non eclipse conditions are
rather small compared to the observed short-term ozone variability.
Furthermore the simulated ozone lifetime is in the range of a few days at
these sites and hence the solar eclipse effects on ozone can be easily
masked by local and regional transport. At the polluted sites of
Thessaloniki and Pallini, the solar eclipse effects on O3, NO2 and
NO concentrations are revealed from both the measurements and modeling with
the net effect being a decrease in O3 and NO and an increase in
NO2 as NO2 formed from the reaction of O3 with NO while at
the same time NO2 is not efficiently photolysed. This result is also
supported by a positive correlation of observed global radiation with O3 and NO and a negative correlation with NO2. It is evident from the
3-D air quality modeling over Greece that the maximum effects of the eclipse
on O3, NO2 and NO are reflected on the large urban agglomerations
of Athens, and Thessaloniki where the maximum of the emissions occur. |
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