Peculiarities of prereverberation formation during long-range propagation of explosion signals

Abstract

In experiments carried out in different regions of the World Ocean on long range propagation of explosion signals, researchers repeatedly observed bistatic surface reverberation that not only accompanied the probing (specularly reflected from the sea surface) signal but also preceded it. The part of the reverberation that preceded the probing signal was called the prereverberation. A theoretical explanation for this phenomenon in the context of an idealized model of the sea surface for the conditions of a near-surface sound channel was presented in 1978, and a technique for calculating the prereverberation time structure with allowance for the real conditions of the sound propagation in the ocean was developed only in the beginning of the 2000s. A series of calculations carried out according to this technique for the conditions of performing two experiments (for a near-surface sound channel and an underwater sound channel with the speed of sound near the bottom exceeding its value near the surface) resulted in the refinement of our knowledge about the mechanism forming the structure of a prereverberation signal. This paper, in addition to a brief description of other authors’ publications on this topic, presents a description of a technique for calculating the time structure of a prereverberation signal, a brief description of the conditions of two experiments in which prereverberation was observed, and results of analyzing the main prereverberation characteristics.