Average Sound Intensities in Randomly Varying Sound-Speed Structures

Abstract

The acoustic field due to a deterministic ocean environment may significantly change, if it is influenced by an additional random variability of the the sound-speed structure. If only the sound intensity has been measured, as in most propagation loss experiments, then the influence of the random variability may be detected in basicly two ways: either by compairing the measured loss with that due to the deterministic ocean or by measuring the scattered energy directly as e.g. in illuminated shadow zones. The first approach requires to define the deterministic environment which may not be a trivial task, while the second approach could discern the presence of substantial variability without relation to the determistic ocean. This will be discussed utilizing two acoustic experiments with considerably different sound speed variability. The two approaches will briefly be related to the so called ‘honest’ and ‘dishonest’ solutions of the stochastic wave equation, and the propagation loss data will be compared to results from stochastic ray tracing.