Modeling reflection loss of the Gaussian rough ocean surface at small incidence angles

Modeling the acoustic reflection loss of the rough ocean surface is a necessary component of a sonar trans- mission model when the scattering field is mainly forward scattering and focuses on the specular direction. To modeling the reflection loss at small angles is of great significance for acoustic field predictions at medium-to-long ranges,especially for shallow oceans or oceans with a surface duct. Firstly, based on the rough ocean surface of Gaussian spectrum, the validity of Ramsurf acoustic propagation model under rough surface conditions is demonstrated through comparison with the propagation data in high state. Moreover, using the modified PE code——Ramsurf as a benchmark, Kirchhoff Approximation (KA) Reflection Loss (RL) model and Small Slope Approximation (SSA) RL model are compared and analyzed. The numerical simulation implies that the SSA model and the results computed by Ramsurf match well. The SSA model is an accurate RL model.