On acoustic wave field response to internal waves in shallow water for variable source position

Acoustic variability is examined using a subset of the swarm\’95 experiment data in our earlier work [J. Acoust. Soc. Am. 108, 2577 (2000)]. Acoustic signals are highly modulated both temporally and spatially due to the presence of internal waves. In addition to energy fluctuations, a large level change in transmission loss was found in the airgun data due to source position changes. The mechanism that contributes to acoustic modulations is mainly due to acoustic mode coupling induced by internal wave propagation. The acoustic modes are decomposed from the data. Mode decorrelation time is examined for different propagation tracks. Fluctuations of the modal correlation indicate an acoustic recorrelation at a longer lag time, which also indicate acoustic intensity variations due to internal waves. Source location was found to be the major factor for high‐energy level variations. It is found that the airgun is depth position sensitive. The acoustic intensity and frequency variations due to source position ch...