Effect of aerosol vertical inhomogeneity on sky background brightness

Numerical experiments have been conducted to simulate the sky background brightness for various aerosol scale heights in order to study the effect of vertical distribution of aerosol on the sky background brightness. A homogeneous model and a vertically inhomogeneous distributed model are utilized to estimate the sky background brightness under the conditions of different ground surface reflectances. The relative differences of sky background brightness as well as the sensitivity of sky background brightness to ground surface reflectance are also shown. The results indicate that the sky background brightness is much different under various aerosol scale heights for given aerosol optical thickness and ground surface reflectance. Moreover,the sky background brightness is also sensitive to the ground surface reflectance and aerosol optical thickness, and the degree of sensitivity is dependent on solar-observation geometry.