Solar radiation scattered within the atmosphere by atmospheric particles and aerosol particles has been investigated with regard to their state of polarization. Therefore measurements are performed with the COmpact RAdiation measurement System CORAS to analyze the individual components of the Stokes vector describing the measured radiation. For this purpose new optical inlets including a polarization filter have been developed. In parallel, radiative transfer simulations are conducted to interpret the measurements. For this purpose, two different radiative transfer solvers (SCIATRAN and polRadtran) were used. The simulations have been compared with the measurements to characterize the aerosol optical thickness and the predominant aerosol type.