Ocean variability effects on sound propagation in shallow water

摘要

In May 1997 SACLANT Undersea Research Centre conducted an experiment south of the Island of Elba off the west cost of Italy to investigate the time variability of received broadband acoustic signals over a 15.5-km fixed propagation path for 36 h.Environmental data were continuously acquired during the acoustic transmissions to establish a meaningful correlation between changes in the ocean and the received acoustic signals. Stability of the acoustic signals in the frequency band 300-850 Hz wasseen up to several hours, but this stability period was reduced to a few minutes for frequencies between 850 and 7500 Hz. Numerical modeling of acoustic propagation through numerically generated sound speed profiles caused by internal waves shows similareffects as observed in the data. The influence of this variability in the synthetic data on source localization is addressed.