Atmospheric Chemistry and Physics www.atmos-chem-phys.net 1680-7316 1680-7324 8 13 2008 10.5194/acp-8-3623-2008 http://www.atmos-chem-phys.net/8/3623/2008/ http://www.atmos-chem-phys.net/8/3623/2008/acp-8-3623-2008.html http://www.atmos-chem-phys.net/8/3623/2008/acp-8-3623-2008.pdf 3623 3637 2008-07-10 The role of iron and black carbon in aerosol light absorption Y. Derimian derimian@loa.univ-lille1.fr A. Karnieli Y. J. Kaufman M. O. Andreae T. W. Andreae O. Dubovik W. Maenhaut I. Koren Major part of this study was done while at: Jacob Blaustein Institute for Desert Research, Ben Gurion University of the Negev, Israel NASA Goddard Space Flight Center, NASA Goddard SFC, USA Max Planck Institute for Chemistry, Mainz, Germany Laboratoire de Optique Atmosphérique, Université de Lille 1/CNRS, Villeneuve d'Ascq, France Ghent University (UGent), Department of Analytical Chemistry, Institute for Nuclear Sciences, Gent, Belgium Department of Environmental Sciences, Weizmann Institute, Rehovot 76100, Israel Iron is a major component of atmospheric aerosols, influencing the light absorption ability of mineral dust, and an important micronutrient that affects oceanic biogeochemistry. The regional distribution of the iron concentration in dust is important for climate studies; however, this is difficult to obtain since it requires in-situ aerosol sampling or simulation of complex natural processes. Simultaneous studies of aerosol chemical composition and radiometric measurements of aerosol optical properties, which were performed in the Negev desert of Israel continuously for about eight years, suggest a potential for deriving a relationship between chemical composition and light absorption properties, in particular the spectral single-scattering albedo. <br><br> The two main data sets of the present study were obtained by a sun/sky radiometer and a stacked filter unit sampler that collects particles in coarse and fine size fractions. Analysis of chemical and optical data showed the presence of mixed dust and pollution aerosol in the study area, although their sources appear to be different. Spectral SSA showed an evident response to increased concentrations of iron, black carbon equivalent matter, and their mixing state. A relationship that relates the spectral SSA, the percentage of iron in total particulate mass, and the pollution components was derived. 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