On the parabolic equation method for water-wave propagation

A parabolic approximation to the reduced wave equation is investigated for the propagation of periodic surface waves in shoaling water. The approximation is derived from splitting the wave field into transmitted and reflected components. In the case of an area with straight and parallel bottom contour lines, the asymptotic form of the solution for high frequencies is compared with the geometrical optics approximation. Two numerical solution techniques are applied to the propagation of an incident plane wave over a circular shoal.