LAUSR

Transmissions of 100–300 Hz sound over distances of 220–505 km in the Beaufort Sea area for 10 months revealed strong long-term trends and short-term variability. The sound was emitted by Canada Basin Acoustic Propagation Experiment (CANAPE) Deep Water sources, and received by CANAPE Shallow Water receivers close to the Chukchi Sea. Much of the sound that arrives at these distances is trapped in the Pacific Water duct. A dynamical model of the area driven by representative forcing, which includes eddies that have propagation consequences, is used to examine changes to the water column at small eddy scales and at broader scales that can influence the sound. Processes such as variable excitation of ducted normal modes, time-variable duct sound-speed mean profile, and coupling of ducted modes to other modes by range dependent eddy features are examined with the model. The effects of these processes are quantified and compared to field observations.Transmissions of 100–300 Hz sound over distances of 220–505 km in the Beaufort Sea area for 10 months revealed strong long-term trends and short-term variability. The sound was emitted by Canada Basin Acoustic Propagation Experiment (CANAPE) Deep Water sources, and received by CANAPE Shallow Water receivers close to the Chukchi Sea. Much of the sound that arrives at these distances is trapped in the Pacific Water duct. A dynamical model of the area driven by representative forcing, which includes eddies that have propagation consequences, is used to examine changes to the water column at small eddy scales and at broader scales that can influence the sound. Processes such as variable excitation of ducted normal modes, time-variable duct sound-speed mean profile, and coupling of ducted modes to other modes by range dependent eddy features are examined with the model. The effects of these processes are quantified and compared to field observations.