The primary objective of the Complex Aerosol Experiment was measurement of microphysical, chemical, and optical properties of aerosol particles in the surface air layer and free atmosphere. The measurement data were used to retrieve the whole set of aerosol optical parameters, necessary for radiation calculations. Three measurement cycles were performed within the Experiment during 2013: in spring, when the aerosol generation is maximal; in summer (July), when atmospheric boundary layer altitude and, hence, mixing layer altitude are maximal; and in late summer – early autumn, during the period of nucleation of secondary particles. Numerical calculations were compared with measurements of downward solar fluxes on the Earth's surface, performed in the clear-sky atmosphere in summer periods in 2010–2012 in a background region of the boreal zone of Siberia. It has been shown that, taking into account the instrumental errors and errors of atmospheric parameters, the relative differences between model and experimental values of direct and global solar radiation fluxes do not exceed, on the average, 1 and 3%, respectively. Thus, independently obtained data on the optical, meteorological, and microphysical parameters of the atmosphere allows intercalibration and inter-complement of the data and, thereby, provide for qualitatively new information which explains the physical nature of the processes that form the vertical structure of the aerosol field.