Sign up & Download
Sign in

Weekly periodicities of Aerosol Optical Thickness over Central Europe – evidence of an anthropogenic direct aerosol effect

by D Bäumer, R Rinke, B Vogel
Atmospheric Chemistry and Physics ()


Statistical analyses of data from ground-based sun photometer stations in Central Europe are presented. All sta- tions 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 Thick- ness (AOT) at awavelength of 440nm of 12 of the 14 stations in the investigation area show a weekly periodicity with low- est 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 an- thropogenic 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 reduc- tion of the direct sun radiation by the columnar atmospheric aerosol, this result represents strong evidence for an anthro- pogenic direct aerosol effect on shortwave radiation. Further- more, this study makes a first contribution to the understand- ing and explanation of recently observed weekly periodicities in meteorological variables as temperature in Germany.

Cite this document (BETA)

Readership Statistics

20 Readers on Mendeley
by Discipline
by Academic Status
35% Ph.D. Student
10% Researcher (at an Academic Institution)
10% Student (Master)
by Country
10% Germany
5% India
5% Spain

Sign up today - FREE

Mendeley saves you time finding and organizing research. Learn more

  • All your research in one place
  • Add and import papers easily
  • Access it anywhere, anytime

Start using Mendeley in seconds!

Sign up & Download

Already have an account? Sign in