Wide‐angle parabolic equation in moving inhomogeneous media

The wide‐angle parabolic equation has been used widely to predict a sound field in an ocean with variations in the adiabatic sound speed c. The same equations with c replaced by the effective sound speed ceff=c+vx has recently been adopted for calculations of sound propagation in a stratified and/or turbulent atmosphere. Here, vx is the wind velocity component in the direction from a source to a receiver. However, as is shown in the presentation, such a replacement does not allow one to correctly take into account the effects of the medium velocity v on sound propagation and scattering in a wide‐angle approximation. Furthermore, the effects of fluctuations in the density ρ on sound scattering are also omitted in this approach. In the presentation, a correct wide‐angle parabolic equation in media with variations in c, ρ and v and its Pade (1,1) approximation are derived. The difference in numerical predictions of sound propagation in a stratified and turbulent atmosphere, based on the equation derived and ...