Chemical, Physical and Optical properties of aerosols during the MINOS campaign
J. Sciare1,2, C. Economou3, H. Bardouki3,
R. Sarda-Estève2, H. Cachier2, M.O. Andreae1 and
N. Mihalopoulos3
1 Max Planck Institute for Chemistry, Department of Biogeochemistry, Mainz, Germany
2 LSCE, CEA Orme des Merisiers, Gif/Yvette, France (sciare@lsce.saclay.cea.fr)
3 University of Crete - Environmental Chemical Processes Laboratory (ECPL), 71409 Heraklion, Greece
Aerosols of both natural and anthropogenic origins can significantly influence earth's
radiative budget through direct/indirect effects. The Eastern Mediterranean is
characterised by high aerosol loading from both natural (Dust / Sea Spray) and
anthropogenic sources (transport from Eastern and Central Europe). The radiative
forcing induced by aerosols in this area could be comparable or even greater, but
opposite in sign, to the forcing induced by the greenhouse gases.
During the MINOS campaign performed during one month period (27/7-22/8) at Crete
Island in the Eastern Mediterranean, several chemical, physical and optical parameters
of aerosols have been monitored:
Ion composition of aerosols has been measured on a 3-h basis for bulk aerosols and on
12-h basis using Stack Filter Units. Carbon content for bulk aerosols (Black Carbon
and Organic Carbon) has been measured on 12-h basis using quartz filters. Total
scattering coefficient (at 550 nm wavelength, Integrating Nephelometer) showed mean
value of 74 Mm-1 (22 to 172 Mm-1). Absorption measurements were estimated from PSAP
(Particle Soot Absorption Photometer) and PAS (Photo Acoustic System) and showed
values ranging from 2.7 to 32.5 Mm-1.
Among the major results of this campaign, a significant dependence on the Relative
Humidity has been observed for both aerosol absorbing and scattering coefficients,
pointing out the water sensitivity of aerosols in the Mediterranean Basin. Further
discussions on optical properties of aerosols will be presented here based on their
chemical composition, physical properties, and air mass origin.