Geometry of Earthshine Reflection from a Spherical Target

摘要

An expression is found for the flux due to earthshine incident at any point on a spherical target as a function of target height above ground. Curves showing the variation of reflected signature (or view factor) with observer position and target height are presented for the case of a diffuse target surface. An expression is given for the view factor in the specular case, which is shown to be independent of observer position. (Author)