Sea clutter reflectivity in ducted propagation

Certain models of sea clutter reflectivity establish a relationship between reflectivity and grazing angle in standard propagation conditions. This paper assumes that grazing angle maps uniquely to phase slope at the surface. A parabolic equation model is used to calculate the surface phase slope for both standard and nonstandard conditions. Lookup tables are calculated which relate phase shape to standard propagation grazing angle and this grazing angle is related to clutter reflectivity. The resulting clutter reflectivity is compared to reflectivity calculated by various empirical and non-empirical models.