Bottom Reverberation in the Presence of Intense Internal Waves

Abstract

The problem of modeling the broadband coherent field of low-frequency bottom reverberation under conditions of hydrodynamic variability associated with the motion of intense soliton-like internal waves (internal wave solitons) is considered. Expressions are obtained for calculating backscattered signals using mode parabolic equations, as well as approximations of coupled modes. It was assumed that the reverberation signal is received from the direction along or across the internal wave front. In the case of mode coupling, it was shown that the presence of a train of internal wave solitons can increase the intensity of bottom reverberation coming from an area of the bottom behind the front of this inhomogeneity if the sound source is at the center of the waveguide. Comparison of the interference patterns of bottom reverberation in a wide frequency band with and without solitons makes it possible to record this disturbance with greater accuracy and at any depth of the sound source. In detecting a reverberation signal under horizontal refraction conditions, an ordered interference pattern is not observed.