Arrays for the Investigation of Ambient Noise in the Ocean

A discussion of the important parameters to be considered in the use of directional arrays for the study of noise fields in the ocean leads to specialized array designs. Some properties of circular and spherical arrays composed of omnidirectional elements are presented. The calculation of directivity index for a spherical array is carried out by the use of the space‐correlation functions of an isotropic noise field. The measured, broad‐band directivity pattern of a circular plane array as a function of frequency is also shown. (This work represents one of the results of research carried out under contract NObsr 72512, NE 120221‐4‐5‐6 with the Bureau of Ships, Navy Department.)