An iteration method for the determination of size distributions of aerosols from spectral attenuation data, similar to the one previously published for clouds, is presented. The basis for this iteration is to consider the extinction efficiency factor of particles as a set of weighting functions covering the entire radius region of a distribution. The weighting functions were calculated exactly from the Mie theory. Aerosol distributions are shown derived from tests with analytical size distributions and also generated from measured aerosol extinction data in seven spectral channels from 0.4-µto 10-µ wavelength in continental aerosols. The influence of relative humidity on the complex index of refraction is also discussed.
H. Grassl, "Determination of Aerosol Size Distributions from Spectral Attenuation Measurements," Appl. Opt. 10, 2534-2538 (1971)