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| Titel |
Three-year ground based measurements of aerosol optical depth over the Eastern Mediterranean: the urban environment of Athens |
| VerfasserIn |
E. Gerasopoulos, V. Amiridis, S. Kazadzis, P. Kokkalis, K. Eleftheratos, M. O. Andreae, T. W. Andreae, H. El-Askary, C. S. 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 ; 11, no. 5 ; Nr. 11, no. 5 (2011-03-10), S.2145-2159 |
| Datensatznummer |
250009452
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| Publikation (Nr.) |
 copernicus.org/acp-11-2145-2011.pdf |
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| Zusammenfassung |
| Three years (2006–2008) of ground-based observations of the Aerosol Optical
Depth (AOD) in the urban environment of Athens, in the Eastern
Mediterranean, are analysed in this work. Measurements were acquired with a
Multi-Filter Rotating Shadowband Radiometer at five wavelengths. The daily
average AOD at 500 nm is 0.23, and the mean Ångström coefficient
calculated between 415 and 867 nm is 1.41. The annual variability of AOD has
a spring maximum dominated by coarse dust particles from the Sahara (AOD
0.34–0.42), while the diurnal pattern is typical for urban sites, with AOD
steadily increasing throughout the day. The greatest contribution to the
annually averaged AOD, accounting for almost 40%, comes from regional and local sources (namely the
Istanbul metropolitan area, the extended areas of biomass burning around the
north coast of the Black Sea, power plants spread throughout the Balkans and
the industrial area in the Po valley, with average daily AOD in the range of
0.25–0.35). An additional important
contribution (23%) is dust from Africa, whereas the rest of Europe
contributes another 22%. The geographical distribution of the above
sources in conjunction with the prevailing synoptic situation and
contribution of local sources, lead to mixed types of aerosols over Athens,
with highly variable contribution of fine and coarse particles to AOD in the
range 10%–90%. This is the first long-term, ground based data set
available for Athens, and it has also been used for the validation of satellite
derived AOD by MODIS, showing good agreement on an annual basis, but with an
overestimation of satellite AODs in the warm period. |
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