Ice-tethered acoustic buoys for real-time active and passive monitoring in the Western Arctic

Abstract

Real-time monitoring of channel impulse response functions in the Beaufort Lens was performed by five Ice-Tethered Acoustic Buoys (ITABs) during March-September 2021. Each ITAB had an eight-element vertical line array and a 900-1000 Hz acoustic source, providing a reciprocal acoustic transmission of up to a 300 km range. Acoustic navigation of one ITAB was successfully tested using the acoustic travel-time from the other ITABs. In addition, a strong single arrival through the Beaufort Lens was observed on each ITAB. Simulations using the measured Q-functions [T. C. Yang, IEEE J. Ocean. Eng. 30(4), 865–880 (2005)] showed a reliable long-range acoustic communication through the Beaufort lens within the 900–1000 Hz frequency band. Finally, a passive ITAB was deployed in March 2022 to measure third-octave under/in-ice ambient noise in the Western Arctic. Both experiments showed that ITABs can be used for under-ice acoustic navigation and communication as well as real-time ambient noise measurements in the Western Arctic. [Work supported by the ONR.]