A parametric analysis of sky radiance and polarization measurements based on a database of calculations indicated that there was information contained in the measurements that was not captured by the database. We therefore developed an iterative algorithm for retrieving a size distribution and size resolved refractive indices of aerosols from cloud free measurements of polarized sky radiances. Preliminary results indicate that it is possible to retrieve a size resolved refractive index for a wide range of aerosol sizes, aswell as an aerosol size distribution.