Horizontal Directionality of Ambient Sea Noise in the North Pacific Ocean
Research and development rept. Sep 1973-Jun 1974
NAVAL UNDERSEA CENTER SAN DIEGO CA
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In September of 1973 the Long Range Acoustic Propagation Project LRAPP Office sponsored a joint exercise, called CHURCH ANCHOR. This was an acoustic and environmental measurement effort conducted in the Northeast Pacific Ocean. This report discusses the results of the ambient noise horizontal directionality measurements from the CHURCH ANCHOR exercise. Measurements were taken along a north-south base line at approximately 143 deg W and extending north from about 31 deg N to 57 deg n. Data from two towed arrays and a circular array are presented. Results indicate that a persistent background noise directionality pattern might exist in the Northeast Pacific Ocean basin, one upon which the fluctuations due to nearby ships and other transients can be considered superimposed. It is suggested that such a persistent noise background directionality pattern is the result of propagation mechanisms which will introduce into the SOFAR channel noise from ships along the basin boundaries and at high latitudes. Once trapped in the channel, the noise travels throughout the basin, aided by the favorable sound transmission.
- Military Intelligence
- Undersea and Antisubmarine Warfare
- Acoustic Detection and Detectors