Forward-scattered contributions in atmospheric transmission measurements

摘要

Abstract: Forward scattering by particles along a transmissometer path can increase the measured transmittance. The contribution of forward scattering is determined by the scattering phase function of the scatterers, their concentration and the optical characteristics of the transmissometer. We present simultaneous measurements of transmittance through fog, rain, and snow made with transmissometers of different wavelength and geometry. Converting the measured transmittances to extinction using the Beer-Lambert law, we find a linear relation between the simultaneously measured extinction values. The linear relationship suggests a simple model for the forward scattering effect. !17