Intensity-Range Relations in Oceanographic Acoustics,
Abstract
A universal graph is presented for constant-depth isovelocity water, with range and frequency both scaled according to the water depth. Five acoustic propagation regions are delineated; spherical spreading, cylindrical spreading, three-halves spreading due to mode stripping, single mode, and bottom path. Very simple derivations of the transmission-loss formulae are given, using an energy-flux approach which allows for the various boundary losses. Comparison is made with experimental intensity-range curves, and also with independent measures of the ray angles or modes effective in carrying the energy. It appears that the simple formulae are meaningful, and useful especially as a guide to understanding. But there are many important extra effects, such as the attenuation due to fish; for which check lists are provided. These extras are different for shallow compared to deep water. A special treatment is included for mode stripping over a sloping bottom, including the case of an arbitrary depth profile. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1971
- Accession Number
- AD0730393
Entities
People
- D. E. Weston
Organizations
- Admiralty Research Laboratory