Abstract

When the Sun or Moon can be seen through clouds, the edge is usually sharp and well defined. Less frequently, but not rarely, the edge will appear hazy or fuzzy through dense cirrus or cirrostratus clouds. Both phenomena have been photographed, and the cloud types associated with each sighting have been analyzed. Simple experiments involving a luminous disk and a variety of scatterers and optical depths have been performed to create both hazy and sharp images. Also, Monte Carlo techniques have been used to investigate under what conditions multiple scattering by clouds can cause the hazy image of the Sun. How horizontal inhomogeneity in clouds on a scale less than the solid angle of the Sun affects the image observed has also been investigated.

© 1992 Optical Society of America