Influence of internal solitary waves on the three-dimensional sound spatial characteristics in shallow sea

Aiming at the problem of the influence of internal soliton waves on the spatial characteristics of sound field in shallow sea environment, a three-dimensional underwater sound field calculation method adapted to soliton internal wave environment is established based on the theory of three-dimensional parabolic equation and its high-precision radical operator approximation method. Considering the propagation characteristics of internal soliton waves and the structural characteristics of the sound field in the form of point source column diffusion in shallow sea, the sound field calculation based on the rectangular coordinate system and cylindrical coordinate system is formed. By changing the input form of environmental parameters, the calculation efficiency is improved, and the three-dimensional sound field distribution characteristics under the influence of internal soliton waves are studied. The results show that the vertical and horizontal distribution structure of the three-dimensional sound field under the influence of internal waves changes and increases with the increase of frequency, especially when the depth of the sound source is near the thermocline. In the non-flat seabed environment, the three-dimensional sound field is modulated by the non-horizontal seabed and internal waves, which leads to the change of the horizontal distribution of the sound field under the influence of the soliton internal waves. This further reflects the horizontal refraction effect of the large-scale non-uniformity of the seabed topography on the sound field and the influence of the sound propagation characteristics to a certain extent.