title: Mean field of a low-frequency sound wave propagating in a fluctuating ocean.
abstract: Statistical characteristics of low-frequency sound waves propagating over long distances in a fluctuating ocean are important for many practical problems. In this paper, using the theory of multiple scattering, the mean field of a low-frequency sound wave was analytically calculated. In these calculations, the ratio of the sound wavelength and the scale of random inhomogeneities can be arbitrary. Furthermore, the correlation function of inhomogeneities is expressed in terms of a modal spectrum (e.g., internal waves modes). The obtained mean sound field is expressed as a sum of normal modes that attenuate exponentially. It is shown that the extinction coefficients of the modes are linearly related to the spectrum of random inhomogeneities in the ocean. Measurements of the extinction coefficients can therefore be used for retrieving this spectrum. The mean sound field is calculated for both 3D and 2D geometries of sound propagation. The results obtained can be used to study the range of applicability of the 2D propagation model.
authors.affiliation: NOAA/Earth System Research Laboratory, 325 Broadway, Boulder, Colorado 80305, USA. alexander.voronovich@noaa.gov
authors.forename: Alexander G
authors.initials: AG
authors.lastname: Voronovich
authors.forename: Vladimir E
authors.initials: VE
authors.lastname: Ostashev