Status: this preprint was under review for the journal AMT. A revision for further review has not been submitted.
Aerosol absorption retrieval at ultraviolet wavelengths in a complex environment
S. Kazadzis,N. Kouremeti,V. Amiridis,A. Arola,and E. Gerasopoulos
S. Kazadzis
Institute of Environmental Research and Sustainable Development, National Observatory of Athens, Greece
N. Kouremeti
Laboratory of Atmospheric Physics, Aristotle University of Thessaloniki, Greece
V. Amiridis
Institute of Astronomy Astrophysics, space applications and remote sensing, National Observatory of Athens, Greece
A. Arola
Finnish Meteorological Institute, Kuopio Unit, Finland
E. Gerasopoulos
Institute of Environmental Research and Sustainable Development, National Observatory of Athens, Greece
Abstract. We have combined sun and sky radiance measurements from a CIMEL sun-photometer and total and diffuse UV irradiance measurements with a multi-filter rotating shadow-band radiometer (UVMFR), in order to calculate aerosol absorption properties (single scattering albedo) in the UV range, for a 10 month period in Athens, Greece. The aerosol extinction optical thickness measured by the CIMEL instrument has been used for the inter-calibration of the UVMFR. The measurements from both instruments were used as input to a radiative transfer model and the single scattering albedo (SSA) for 368 nm and 332 nm has been calculated. The SSA values at these wavelengths, together with synchronous SSA, CIMEL-derived, retrievals at 440 nm, show a mean of 0.88, 0.86 and 0.80, with lowest values (higher absorption) towards lower wavelengths. In addition, noticeable diurnal variations of the SSA in all wavelengths are revealed, with amplitudes in the order of 0.05. Higher SSA wavelength dependence is found for cases of lower Ångström exponents and also an SSA decrease with decreasing extinction optical depth, suggesting an effect of the different aerosol composition.