Long‐range sound propagation across Atlantic Ocean seamounts: Implications for ambient noise

Abstract

A low frequency (50–800 Hz) sound‐propagation experiment was conducted along a 1400‐km path running eastward from Bermuda toward the Mid‐Atlantic Ridge. SUS charges were detonated at depths of 18, 154, 615, and 1230 m. The receiver was located at the axis of the deep sound channel (1250 m) at a range of approximately 1300 km. The acoustic path crossed several seamounts of the Corner Seamount Group. The highest of these peaks rose to the sound axis. This paper presents the relative enhancement of signal level for SOFAR propagation due to these seamounts as a function of source depth and frequency. The enhancement was minimal for the 1230‐m shots, while the greatest enhancement occurred for the 18‐m shots at the 50‐Hz filter band. This implies these seamounts and other topographic features such as the Mid‐Atlantic Ridge can significantly increase the coupling of low‐frequency ship‐generated noise into the deep sound channel. [Work supported by NAVSEA.]