Listening to the changing Arctic Ocean

The changing climate is changing the Arctic Ocean. Ice, however, makes it challenging to track these changes, so scientists turn to sound. Acoustic signals transmitted beneath the ice can reveal this concealed environment.

From 2019 to 2020, the joint US-Norwegian Coordinated Arctic Acoustic Thermometry Experiment (CAATEX) used six bottom-anchored moorings across the Arctic Ocean to transmit and measure acoustic signals every three days. Dzieciuch et al. present and analyze data on the oceanographic environment from CAATEX.

The authors found during CAATEX that signals could be transmitted over 2,600 kilometers at a higher frequency than in previous experiments conducted in the 1990s. The high frequency sounds may be able to travel farther due to thinner ice.

“Our work advances the use of acoustics to study the Arctic Ocean,” said author Hanne Sagen. “The results show that long-range acoustic measurements can be made reliably across the Arctic to provide continuous, year-round observations in one of the hardest regions on Earth to monitor.”

“Further, the acoustic travel times were found to vary significantly over the year,” added author Matthew Dzieciuch. Information on the large-scale variability in the Arctic Ocean on timescales of less than a year is not available from other types of measurements.

Next, the authors will use measurements from CAATEX to estimate range-averaged sound speed, which will allow them to figure out the temperature along the acoustic paths.

“Basin-scale temperature measurements every three days under sea ice will fill a critical observational gap, advance our ability to track large-scale ocean variability, and strengthen the foundation for understanding and predicting Arctic climate change,” Sagen said.

Source: “Transarctic acoustic transmissions during the coordinated Arctic acoustic thermometry experiment in 2019–2020,” by Matthew A. Dzieciuch, Hanne Sagen, Peter F. Worcester, Espen Storheim, F. Hunter Akins, Stein Sandven, John A. Colosi, John N. Kemp, and Geir Martin Leinebø, Journal of the Acoustical Society of America (2026). The article can be accessed at https://doi.org/10.1121/10.0042233 .

This paper is part of the Climate Change: How the Sound of the Planet Reflects the Health of the Planet Collection, learn more here .