Near-Axial Interference Effects for Long-Range Sound Transmissions through Ocean Internal Waves

Abstract

Abstract : The long-term goal of this effort is to provide an improved way of interpreting the experimentally observed time-of-arrival patterns in long-range, low-frequency propagation in the deep ocean. In many long-range propagation studies the source and receiver are placed close to the depth of the waveguide (SOFAR) axis to minimize the interaction of the acoustic field with the ocean's surface and bottom. The most pronounced characteristics of the time-of-arrival patterns for these experiments are early geometric-like arrivals followed by a crescendo of energy that propagates along the axis. In Fig.1 adapted from one published in Ref. (1) these characteristics are clearly shown for a time-of-arrival pattern measured during the Acoustic Engineering Test (AET) of the Acoustic Thermometry of Ocean Climate (ATOC) project conducted in the eastern North Pacific Ocean.