Phenomena during the growth and decay of spread-F

Observations of the directional distribution of ambient sea noise are reviewed, for depths of 100 to 1000 feet, in the octave 0.75 to 1.5 kc/s, obtained with a 32-element spherical array yielding 32 simultaneous beams covering all directions in three dimensions. The results are presented diagrammatically. An appendix contains a description of the DIMUS bea m-forming system (clipping and shift-register delays) which is employed.