A method for single-hydrophone geoacoustic inversion based on the modal group velocities estimation: Application to a waveguide with inhomogeneous bottom relief

Recently a new geoacoustic inversion method was introduced in the works [1, 2] for the approximately range-independent shallow-water waveguides. It allows estimation of the acoustical parameters of the seabed (sound speed, density, etc) and the range from the source to the receiver using the recording of the pulse signal by a single hydrophone. This method is based on the use of the so-called warping transform [3], a nonuniform resampling which helps straighten dispersive curves of individual modes and greatly improve mode separability [1]. The dispersive curves separated from each other allow us to extract the information about the modal delay times (or modal group velocities) which may be used for the inversion of media parameters. In this paper we present a generalization of this inversion method to the case of the range-dependent waveguides with slowly varying bottom relief.