Detecting the Kauai source beacon with ocean observatories innitiative hydrophones

Abstract

In March of 2023, a sound source off the coast of Kauai began regularly transmitting a 75 Hz signal into the ocean, six times a day, every fourth day. The regular transmission of this signal allows for the long-term measurements of ocean basin scale temperature changes using the technique of acoustic tomography, as well as further investigations of long-distance acoustic propagation. The Ocean Observatory Initiative (OOI) has, as part of its suite of oceanographic sensors, 11 hydrophones that are continually recording ambient sound. These hydrophones are in various diverse environments in the north-east pacific including bottom mounted in shallow environments, deep environments, on top of seamounts, and moored at 200 m below the ocean surface. In this talk, we present preliminary results of acoustic propagation modeling and data analysis towards receiving the Kauai signal with the OOI hydrophones. The diverse environments of the hydrophones allow us to investigate how different levels of ambient sound and environmental factors, such as proximity to the sound channel affect the ability to detect a positive reception of the Kauai source across the ocean basin. [Work supported by ONR.]