An overview of SAX99: Acoustic measurements

A high-frequency acoustic experiment was performed at a site 2 km from shor e on the Florida Panhandle near Fort Walton Beach in water of 18-19 m depth , The goal of the experiment was, for high-frequency acoustic fields (mostl y in the 10-300-kHz range), to quantify backscattering from the seafloor se diment, penetration into the sediment, and propagation within the sediment. In addition, spheres and other objects were used to gather data on acousti c detection of buried objects, The high-frequency acoustic interaction with the medium sand sediment was investigated at grazing angles both above and below the critical angle of about 30 degrees. Detailed characterizations o f the upper seafloor physical properties were made to aid in quantifying th e acoustic interaction with the seafloor. Biological processes within the s eabed and the water column mere also investigated with the goal of understa nding their impact on acoustic properties. This paper summarizes the topics that motivated the experiment, outlines the scope of the measurements done , and presents preliminary acoustics results. A preliminary summary of the meteorological, oceanographic, and seafloor conditions found during the exp eriment is given by Richardson ef al. [1].