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| Titel |
Weekly periodicities of Aerosol Optical Thickness over Central Europe – evidence of an anthropogenic direct aerosol effect |
| VerfasserIn |
D. Bäumer, R. Rinke, B. Vogel |
| 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 ; 8, no. 1 ; Nr. 8, no. 1 (2008-01-14), S.83-90 |
| Datensatznummer |
250005337
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| Publikation (Nr.) |
 copernicus.org/acp-8-83-2008.pdf |
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| Zusammenfassung |
| Statistical analyses of data from ground-based sun photometer stations in
Central Europe are presented. All stations are part of the Aerosol Robotic
Network (AERONET), and only data of the highest data quality level 2.0 has
been applied. The averages by weekday of Aerosol Optical Thickness (AOT) at
a wavelength of 440 nm of 12 of the 14 stations in the investigation area
show a weekly periodicity with lowest values on Sunday and Monday, but
greatest values from Wednesday until Saturday, that is significant at least
on a 90% level. The stations in Germany and in Greater Paris show weekly
cycles with ranges of about 20% on average. In Northern Italy and
Switzerland this range is about 10% on average. By applying several
checks, we exclude that the weekly cycles were caused by a maintenance
effect or by different retrieval conditions as a consequence of a weekly
cycle in cloud cover. The corresponding weekly cycle of anthropogenic
gaseous and particulate emissions leads us to the conclusion of the
anthropogenic origin of the weekly AOT cycle. Since these AOT patterns are
derived from the reduction of the direct sun radiation by the columnar
atmospheric aerosol, this result represents strong evidence for an
anthropogenic direct aerosol effect on shortwave radiation. Furthermore,
this study makes a first contribution to the understanding and explanation
of recently observed weekly periodicities in meteorological variables as
temperature in Germany. |
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