Comparison of Convergence-Zone-Measured Sound Pressures in the Deep Ocean with Pressures Computed from the Sound Speeddepth Function

摘要

This report is a sequel to an earlier report (AD-606 391) in which the sound speed c was determined as a function of the depth z in deep-ocean waters north of Puerto Rico. Computational methods were also developed and used to obtain numerical values for the horizontal range between the sound source and the zone where the emitted acoustic waves converge to give signal (pressure) enhancement. The present report is concerned with computing the detailed distribution of sound pressure, by means of ray diagrams and field measurements, in the zone. On the basis of simple wave theory, convergence zone ranges and pressure values are derived from the c(z) function for three basic ray fans which overlap at the zone. It is found that both the horizontal range determinations (from 64.34 to about 70 km) and the acoustic pressure values within the zone agree favorably with measured values. By utilizing deep-ocean measurements, the resultant acoustic pressures were free of confusion from bottom scattering and the complexity of many refraction paths. (Author)