Passive acoustic estimates of sound speed from vertical line array data in the Nordic Seas.

In wind-wave driven ambient sound environments, the cross-correlation of acoustic data recorded on vertically separated hydrophones can provide estimates of the average sound speed between hydrophones. Deployment of a 52-element vertical line array of hydrophones located on a 425 m deep ridge in the Nordic waters near Jan Mayen Island enabled estimates of the water column sound speed profile. Sound speed profiles were estimated for each 24-min recording, which were collected every four hours over the course of the year-long experiment, supplying a wide range of environmental conditions. Over the full experiment, estimated sound speeds had a root-median-square error of 0.79 m/s when compared to direct measurements.