Role of the Seabed in Low-Frequency Shallow-Water Acoustic Propagation: Examplesfrom Measurements and Modelling

摘要

Except in rather unusual circumstances, interaction with the seafloor is aninevitable accompaniment to the propagation of sound in the sea. In shallow water, especially at very low and low frequencies, the bottom interaction plays a significant, if not deterministic, role in acoustic propagation. From the results of numerous experiments and numerical modelling in recent years, it is evident that one must account for the geoacoustic properties in more than an ad hoc fashion. Some of the relevant research efforts, particularly those from the ongoing research program at the NOARL, are described in this paper. The results of the NOARL measurements in several geographical areas, coupled with numerical modelling, are used to demonstrate the significance of energy partitioning between waterborne and bottom paths, the role of Scholte interface waves, the efficacy and limitations of selected numerical models, and the significance of ambient noise. Keywords: Underwater sound transmission; Underwater acoustics interactions. (edc)