Propagation-Loss Measurements and Modelling for Topographically Smooth and Rough Seabeds.

摘要

Acoustic propagation loss data were obtained along two radial tracks from a receiving array at a site on the Scotian Shelf. One track was over a smooth seabed and the other over a rough seabed. The features of the propagation loss data for the two seabed types have been analyzed and compared. At-sea measurements show that fluctuations in the propagation loss data are correlated with water-depth variations for the case of the rough seabed. Two different propagation-loss modelling programs are used in an attempt to explain the acoustic features observed over the two seabeds. The majority of the modelled results were obtained with PROLOS, a DREA-developed range-dependent normal-mode program. The results of a ray-trace propagation-loss model (GRASS are also compared with the measured data. The ray-trace model provides insight on which acoustic transmission paths are most important, while PROLOS is able to model the propagation-loss over both the smooth and rough seabeds surprisingly well. Keywords: Underwater acoustics; Shallow water; Hydrophone arrays; Underwater sound transmission; Marine geophysics; Continental shelves; Submarine topographic features; Surface roughness, Canada. (SDW)