Measurements of transmitted urban light through clouds that are provided by nocturnal satellite images yield information regarding the optical parameters of clouds. While the albedo for optically thick clouds becomes insensitive to changes in optical thickness, the fractional change in the zenith-directed transmission of city light through thick clouds is relatively sensitive to changes in optical thickness. Models are derived and evaluated to compute the radiances from Lambertian point and extended light sources that are transmitted toward zenith through clouds of varying albedos for single scattering, asymmetry factors, cloud heights, and optical thickness. lt is shown that radiances from reflected moonlight and transmitted city light may be used to estimate van de Hulst's similarity parameters of clouds above and near cities. ¿American Geophysical Union 1987