Acoustic propagation influenced by an anticyclonic eddy near Jan Mayen Island

This paper presents measurements collected on a vertical line array (VLA) of hydrophones moored near Jan Mayen Island, an area where warm, salty Atlantic waters mix with fresher polar waters from the Greenland Basin. The dataset compares signals simultaneously collected along two propagation paths: a moored source located 42 km north of the array and a drifting source that originated near the array and then moved northeast. Water-column properties were measured extensively using sensors on the moorings, on the buoy of the drifting source, and on ship deployed instruments. The water-column sound-speed profile included a warm surface mixed layer and a subsurface acoustic duct with an axis near 200 m. Both the moored and drifting sources were located at a depth of 100 m, and signals from both sources presented a ducted arrival measured on the VLA. While the sound-speed conditions between the moored source and VLA were more quiescent, the drifting source became trapped in an eddy with a deep mixed layer, intensifying the downward refraction of sound, and lengthening the ray cycle distance. As the source opened to a range of 43 km, the ducted path became bathymetrically blocked, and the signal could no longer be detected.