Influence of internal waves on sound propagation in the SOFAR channel

Abstract

In this paper theoretical investigations due to the influence of internal waves to sound propagation in the SOFAR-channel are presented. The undisturbed acoustic field is described by a normal-mode model. The disturbance by internal waves is considered in the two limits. 1) The internal wavelengths are large compared with acoustic wavelengths. The result is a phase fluctuation for each individual mode. Interference of the total mode field yields amplitude fluctuations as well. 2) Internal wavelengths cannot be considered large compared with acoustic wavelengths. Then acoustic energy is transferred from mode to mode. This problem is treated by the theory of resonant wave-wave interaction (Bragg scattering). Numerical results are presented and compared with published experiments.