Modelling low grazing angle electromagnetic scattering from the sea surface

We review the integral equation (IE) description of low grazing angle scattering of microwaves, in the main by extended corrugated structures modelling the sea surface and accounting for their effectively infinite extent through the adjunct plane (AP) construction. Solution of the discretised IE by an iterative scheme that incorporates an improved method for the evaluation of the AP contributions is discussed. Perfectly and imperfectly conducting scatterers are considered separately; we attempt to recover the simplicity and physical transparency apparent in the analysis of the former and, to a certain extent, mislaid in earlier discussions of the latter. Results are presented that highlight the impact of shadowing and multiple scattering processes in the low grazing angle scattering regime. Our summary of the underlying mathematical principles of these calculations is complemented by a discussion of several practically useful insights they can provide.