Monitoring the ocean climate with acoustics

Abstract

Underwater acoustics has developed into a powerful tool for monitoring the climate of ocean basins. Acoustic travel-times are a direct indication of ocean temperature and give a large-scale average of heat content. A recent experiment called the Coordinated Arctic Acoustic Thermometry Experiment (CAATEX) is a prime example of the method in a region known to be experiencing the most rapid response to anthropogenic forcing. In CAATEX, two 35 Hz acoustic transceiver moorings, one in the Nansen Basin and one in the Beaufort Sea, were deployed along with four other receiving moorings. The travel-times between these moorings provide an accurate baseline of the environment during the 2019–2020 deployment year that can be compared to past, present, and future measurements and climatologies. Furthermore, other acoustic observables, such as transmission loss and the ambient soundscape, provide important insight into the ice conditions and the changing environment.