One of the goals of the aerosol column closure experiment Lindenberg Aerosol Characterization Experiment (LACE 98) that was carried out over the eastern part of Germany in summer 1998 was to reduce uncertainties in the determination of the radiative effects of aerosol particles over land. For this purpose, a variety of closure experiments was carried out during LACE 98 to determine the chemical, physical, optical, and radiative properties of the aerosols during situations of clean and strongly polluted continental air. By coordinated flights of three aircraft, measurements of aerosol microphysical and optical properties, of spectral surface reflectance, and of upwelling and downwelling solar irradiances were performed at altitude levels between 200 m and 11 km. The measurements are used for a comparison with results from a radiative transfer model. The calculations are based on measured aerosol properties such as the total number concentration and particle size distribution. The chemical composition of the aerosol was obtained from an analysis of filter samples in order to obtain the optical properties of the aerosol throughout the relevant spectral range by use of Mie theory. The results for the daily averaged solar radiative forcing due to aerosol particles reveal cooling of the total Earth/atmosphere system ranging from -4 to -13 W m-2 in cloud-free conditions.