Aerosol physical and optical properties in the Eastern Mediterranean Basin, Crete, from Aerosol Robotic Network data A. Fotiadi1,2, N. Hatzianastassiou2,4, E. Drakakis2,3, C. Matsoukas2,5, K. G. Pavlakis1,2,7, D. Hatzidimitriou1,2, E. Gerasopoulos6,8, N. Mihalopoulos6, and I. Vardavas1,2 1Department of Physics, University of Crete, Crete, Greece 2Foundation for Research and Technology-Hellas, Heraklion, Crete, Greece 3Department of Electrical Engineering, Technological Educational Institute of Crete, Greece 4Laboratory of Meteorology, Department of Physics, University of Ioannina, Greece 5Department of Environment, University of the Aegean, Greece 6Environmental Chemical Processes Laboratory, Department of Chemistry, University of Crete, Greece 7Department of General Applied Science, Technological Educational Institute of Crete, Greece 8Institute for Environmental Science and Sustainable Development, National Observatory of Athens, Athens, Greece
Abstract. In this study, we investigate the aerosol optical properties, namely aerosol
extinction optical thickness (AOT), Angström parameter and size
distribution over the Eastern Mediterranean Basin, using spectral
measurements from the recently established FORTH (Foundation for Research
and Technology-Hellas) AERONET station in Crete, for the two-year period
2003–2004. The location of the FORTH-AERONET station offers a unique
opportunity to monitor aerosols from different sources. Maximum values of
AOT are found primarily in spring, which together with small values of the
Angström parameter indicate dust transported from African deserts,
whereas the minimum values of AOT occur in winter. In autumn, large AOT
values observed at near-infrared wavelengths arise also from dust transport.
In summer, large AOT values at ultraviolet (340 nm) and visible wavelengths
(500 nm), together with large values of the Angström parameter, are
associated with transport of fine aerosols of urban/industrial and biomass
burning origin. The Angström parameter values vary on a daily basis
within the range 0.05–2.20, and on a monthly basis within the range 0.68–1.9.
This behaviour, together with broad frequency distributions and
back-trajectory analyses, indicates a great variety of aerosol types over
the study region including dust, urban-industrial and biomass-burning
pollution, and maritime, as well as mixed aerosol types. Large temporal
variability is observed in AOT, Angström parameter, aerosol content and
size. The fine and coarse aerosol modes persist throughout the year, with
the coarse mode dominant except in summer. The highest values of AOT are
related primarily to southeasterly winds, associated with coarse aerosols,
and to a less extent to northwesterly winds associated with fine aerosols.
The results of this study show that the FORTH AERONET station in Crete is
well suited for studying the transport and mixing of different types of
aerosols from a variety of sources, especially those associated with major
dust events from the Sahara.
Citation: Fotiadi, A., Hatzianastassiou, N., Drakakis, E., Matsoukas, C., Pavlakis, K. G., Hatzidimitriou, D., Gerasopoulos, E., Mihalopoulos, N., and Vardavas, I.: Aerosol physical and optical properties in the Eastern Mediterranean Basin, Crete, from Aerosol Robotic Network data, Atmos. Chem. Phys., 6, 5399-5413, doi:10.5194/acp-6-5399-2006, 2006.