Combined Acoustic Propagation in Eastpac Region (Exercise CAPER): Initial Acoustic Analysis
Abstract
This report presents an initial acoustic assessment of Exercise CAPER, which was conducted during August 1974 in an area about 830 km west of San Diego, California. The principal objective of this exercise was to measure experimentally the interference of CW signals caused by a well-surveyed isolated seamount, in this case Stoddard Seamount. The report discusses three major areas of analysis. The first area is the convolution of ray diagrams with the bathymetry of the seamount in order to delineate the shadow zones formed behind the seamount. The second area is the detailed comparison of acoustic ranges and satellite navigation ranges. The third area is to assess the effect of range- dependent profiles as measured on CAPER. The design and execution of the various seamount shadowing runs well satisfy the goals of the exercise. The major effect of the seamount is to intercept the leading portion of the convergence zones. Comparison of the differences between 52 acoustic and satellite ranges showed a mean difference of 117 m with a standard deviation of 272 m. The maximum difference was -726 m, while 88 % of the differences fell within + or - 366 m. There was propagation through four distinct near-surface water masses. A comparison of ray calculations for a single profile appropriate for the receiver with calculations using all four profiles demonstrated the importance of horizontal change. Range differences of as much as 13.2 km were calculated for the eighth convergence zone. Sound speeds within 18 km of the seamount peak were about 0.22 microsec higher than in the surrounding ocean for depths from 1000 to 2500 m.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1978
- Accession Number
- ADB032496
Entities
People
- M. A. Pedersen
- R. F. Hosmer