Frequency‐dependent influence of the sea bottom on the near‐surface sound field in shallow water

Abstract

The influence of the sea bottom on shallow‐water sound propagation can be especially pronounced for the sound field near the boundaries. Comparison of the near‐surface sound field with the mid‐depth field, for example, can serve as a useful diagnostic tool for understanding the frequency‐dependent influence of the sea bottom on sound propagation in shallow water. Broad‐band shallow‐water sound‐propagation data analyzed in one‐third octave bands are compared for a very shallow receiver (2 m) and a mid‐depth receiver (50 m). The data are also compared with results from modal calculations. The interplay between the behavior of the modal depth functions and modal attenuations, as frequency is varied, provides a convenient model for interpreting the results.