Broadband acoustic data (30–160 Hz) from the SWARM'95 experiment are analyzed to
investigate acoustic signal variability in the presence of ocean internal waves. Temporal
variations in the intensity of the received signals were observed over periods of 10 to 15 min.
These fluctuations are synchronous in depth and are dependent upon the water column
variability. They can be explained by significant horizontal refraction taking place when the
orientation of the acoustic track is nearly parallel to the fronts of the internal waves. Analyses …