Determination of aerosol size distribution from observation of the aureole around a point source 1: Theoretical

A theoretical basis is presented for a new method for determining the aerosol size distribution from aureole measurements around a point source. The method involves the determination of the angular scattering coefficient from radiance measurements at different observation angles between 1° and 10° around a source in the solar blind spectral region. The results are used to determine the aerosol size distribution by applying the Twomey-Chahine inversion algorithm. The derived size distribution has the desirable features of being accurate for large particles up to radii of 10 μm and being insensitive to their complex refractive index.