Home page of the Russian Acoustical Society Proceedings of the X Session of the Russian Acoustical Society
Ocean Acoustics

A.V. Furduev
Andreyev Acoustics Institute,
ul. Shvernika 4, Moscow, 117036 Russia.


Data are presented on testing new methods to monitor the medium variability on a sea shelf. The difference-pulse technique is considered, in which the information on medium variations is carried by the difference between two amplitude-time sequences of pulses that passed over the propagating path. The regenerative monitoring scheme is analyzed, according to which the signal and ambient noise received by a hydrophone are retransmitted from a distant point of the fixed path. Thereby a closed scheme is formed, with the acoustic path serving as the feedback loop. The regeneration and self-excitation regimes are considered. With the latter regime, the information on the medium variability is carried by the frequency deviation of the self-sustained oscillator - a device that involves the medium to be monitored. The results of tests showed a high sensitivity of the methods to hydrophysical and technogenic inhomogeneities on the path, to variations in the mean water temperature, and to the current velocity.