A shallow-water reverberation PE model

A numerical model (REVPA) has been developed to predict long-range shallow water reverberation. This model is based on a wide-angle parabolic equation (fourth order Pade approximation) and takes reverberation phenomena into account by means of a scattering index. The coupling between the PE model and the indexes is performed, at each range step, by means of a plane-wave decomposition. Two different decomposition methods are implemented in REVPA: a spatial Fourier transform (which is generally used in PE models) and a modal decomposition based on the WKB approximation. Different simulations are presented (for a constant and a variable sound speed profile), the results of which are compared to the normal mode model R-SNAP.