ASA 125th Meeting Ottawa 1993 May

4pUW1. Low-frequency bottom scattering strengths for a shallow water site in the Gulf of Mexico.

Peter G. Cable

BBN Systems and Technol., Union Sta., New London, CT 06320-6147

Theo Kooij

Mike Steele

BBN Systems and Technol., Arlington, VA 22209

Acoustic transmission and reverberation measurements from 25 Hz to 1 kHz were made in 100 fathom water on the West Florida Shelf during Area Characterization Test I (ACT I) in September 1992. Explosive charges were detonated at 90-m depth and reverberation data were received on collocated vertical and horizontal hydrophone line arrays, each array having 25 hydrophones in nested sub-apertures designed for 100, 200, and 400 Hz. Near-monostatic source-to-receiver separation (2 km) and bistatic separations of 10 to 40 km in 10-km increments were employed in the test. From the reverberation data and the transmission loss measurements total monostatic and bistatic bottom scattering strengths have be determined and compared. Also, from the vertical array data monostatic scattering strengths versus scattering angle have been determined. The scattering strengths from ACT I have been compared with determinations from other shallow water measurements having similar bottoms. In addition, these results have been compared with angle and frequency dependencies for different scattering models. [Work supported by the DARPA Adverse Environments Program.]