2023 Volume 79 Issue 18 Article ID: 23-18127
Active sonar is useful for monitoring poachers and terrorists lurking in and around harbors, however its detectable range is highly dependent on the propagation characteristics of high-frequency sound waves in extremely shallow waters. Offshore wind turbines installed in coastal areas can be a source of noise in the sea and affect the acoustic environment, the extent of which depends largely on the propagation behavior. In this paper, the propagation characteristics of high-frequency sound waves in extremely shallow water are studied by conducting experiments over a distance of several hundred meters in a bay with water depths shallower than 20 m, where the seafloor topography varies; these results are also compared with a numerical analysis using BELLHOP, which is a simulation method based on the modified ray tracing method using Gaussian beams. Considerable agreement between the two is observed as long as the acoustic properties of the marine sedimentary layers required as input parameters for the calculations are properly configured, so as to be expected in its application to the prediction of the acoustic environment in extremely shallow waters.
