Propagation Loss in a Heterogeneous Medium Bounded by a Rough Surface

A general method is described for calculating the average sound‐intensity field due to a directional source in a fluctuating refractive and absorbing medium contained within a random‐scattering and ‐absorbing surface. The following is assumed—the radiation is completely incoherent as a result of random fluctuations of the medium and surface; radiation propagates along ray paths determined by the given average sound‐velocity field; the statistical properties of the rough surface are given on the average surface. An integral equation determines the intensity at the average surface. The intensity in the medium is the sum of radiation directly from the source and an integral over the whole surface of scattered radiation directly for points of the surface. The method is applied to surface‐duct propagation in the sea and numerical results are discussed from a simplified adjustable‐parameter model of the ocean. [Work supported by U. S. Navy Ordnance Systems Command.]