Shadowing of random rough surfaces

To account for shadowing in investigations of scattering by rough surfaces, the area subtending the surface is multiplied by a shadowing function equal to the ratio of illuminated to total area. This is derived for a surface generated by a stationary process in general and a normal process in particular. The resulting height distribution of the surface, when only its illuminated parts are considered, is also derived; this is used to determine the effect of shadowing by a more rigorous method.