Abstract
The complex index of refraction, scattering cross section and albedo for single scattering have been estimated from measurements of the angular distribution of light scattered by aerosol particles, by an inversion library method. The humidity dependence of these optical properties has been examined in compiling 250 samples for the period FebruaryNovember 1978. It is found that optical properties of aerosol particles change systematically according to the change of relative humidity. The humidity dependence of the complex index of refraction is explained by Hänel's theory introducing the mean mass increase coefficient for atmospheric aerosols consisting of both water-soluble and insoluble substances and the value of 1.58-0.04 i for the complex index of refraction of dry particles.
Preliminary experiments of controlled relative humidity have also been performed to confirm the above results.
