Azimuthal dependence of sound propagation due to seabed variability in shallow water

Abstract

In shallow water regions, the environment has complicated temporal and spatial variability including changes of bathymetry, sediment layer structure, bottom property, and physical oceanographic spatial and temporal changes due to processes like internal waves. All these effects can influence sound propagation in the waveguide. The azimuth angle dependence of sound propagation has been studied using the broadband acoustic signals measured at the Atlantic Generation Station site on the New Jersey continental Shelf, where two distinctive geologic/geoacoustic regions exist [J. Acoust. Soc. Am. 96(6), 1994]. The current paper revisits this idea by analyzing the modal dispersion of broadband acoustic signals deployed along circular tracks at the site of the Seabed Characterization Experiment 2017, where the seabed shows strong azimuthal dependent sub-mud layer ridges overlaid by a relatively uniform mud layer with variable thickness along different directions. The results of this paper can be utilized to assess the azimuthal dependence of the sound propagation in the mud patch region. [Work supported by ONR Ocean Acoustics.]