Bottom reflection phase inversion using modal dispersion curves

A technique to obtain an estimate of the seabed reflection coefficient phase from modal dispersion curves is presented. The technique is demonstrated on experimental data with a frequency range of 4 to 100 kHz in a 10‐cm‐deep water waveguide. Thirteen modal dispersion curves, defined as the pressure amplitude as a function of frequency and horizontal wave number, were obtained by measuring the acoustic pressure as a function of range and performing a Hankel transform. Initial attempts have produced estimates of the phase that are in close agreement with an independent estimate obtained by measuring the seabed wave speeds and density. [Work sponsored by EPSRC and DERA (Winfrith).]