Acoustic Transmission Loss in Shallow-Water Waveguides with an Sloping Bottom

The paper analytically demonstrates that for a shallow-water waveguide, there can be found an "optimal" bottom profile for which the energy losses with range will be the lowest, provided the initial and final depths are fixed and the depth increases monotonically. The analytical estimates given by the normal mode method are confirmed by a numerical experiment using a wide-angle parabolic equation. For the optimal profile, the features of the sound field behavior, its intensity with range from the source, and mode coupling are investigated.