Mode enhancement using a vertical array of transmitters: Theory and experiment

Abstract

A vertical transmitting array was implanted in Block Island Sound in November 1970. Tests conducted in 1972 and 1973 in the Block Island area used this array to transmit energy at 1700 Hz and used a vertical array of receivers to probe the sound field in range and depth. The measurements served as a test of the possibility of enhancing selected modes in the sound field by weighting the transmitting array elements in a manner which matched the field of a selected mode. In addition, they tested the ability of an acoustic model to predict propagation loss as a function of range and depth for a vertical array of sources. Long-term oceanographic data were also taken using temperature sensors attached to the tower containing the transmitting array. These data were used to determine both the long- and short-term temporal stability of the medium and the resulting effect on mode enhancement as a function of frequency. [This project was funded by NAVSEA (SEA 06H1-4).]