Recent Methods for the Measurement of Sound Transmission in the Ocean

Abstract

The transmission of sound in the ocean has recently been investigated by two methods. In one, a transducer mounted on a submarine served as a sound source of controllable depth, range, and frequency. A string of six hydrophones suspended from a surface vessel enabled the sound field to be measured at six different depths. Measurements at eight and sixteen kilocycles were obtained on a cruise in Caribbean waters and have been plotted as transmission anomaly cross sections showing contours of equal sound level after the removal of spherical divergence. In the other method, the submarine was replaced by a surface vessel from which a sound projector could be lowered to specified depths. This method, employed on a cruise in Middle Atlantic waters, permits longer ranges to be reached, but yields a density of data insufficient for contouring. A second method of lucidly representing the sound field is given.