Bottom Characteristics and Shallow Water Sound Propagation : An Acoustician's View at Mid-Frequencies (500 - 5000 HZ)
Abstract
Interaction with the bottom can certainly be a dominant factor in shallow water sound propagation, hence there is a renewed interest in understanding bottom characteristics. A study of 10 typical shallow water sites indicates the extent of this problem, at least from an acoustician's perspective. Perhaps surprisingly, strong bottom interaction due to a totally downward refracting sound speed profile occurred only 25% of the time, with some form of ducting occurring the remaining time. Eight of the locations had a "hard" or "fast" bottom which results in a step-like bottom loss, with the increase occurring at the critical angle. It was typically found, under downward refracting conditions, that sources and receivers located near the bottom would have dominant propagation paths with less-than-critical-angle bottom interactions and hence, relatively low propagation loss. Sources near the surface, on the other hand, may have steeper angle interactions, higher bottom loss, and correspondingly higher propagation loss. Therefore, the sound speed profile, source/receiver location, water depth, and propagation range must all be considered to anticipate the extent of the bottom interaction.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 21, 1993
- Accession Number
- ADA637145
Entities
People
- David G. Browning
- Joseph M. Monti
- Peter D. Herstein
Organizations
- Naval Undersea Warfare Center