Characterization of the Environment During SAX04: Preliminary Results
NAVAL RESEARCH LAB STENNIS SPACE CENTER MS SEAFLOOR SCIENCES DIRECTORATE
Pagination or Media Count:
The Sediment Acoustic Experiment SAXO4 was conducted on a sandy sediment 1- km offshore of Ft. Walton Beach, Florida, September-November, 2904. The objectives of SAXO4 were to provide a fundamental understanding of high frequency acoustic-bottom interactions sufficient to predict acoustic scattering from the seafloor, penetration of acoustic energy into the seafloor, and propagation of acoustic energy within the seafloor. For these acoustic topics a thorough characterization of seafloor properties is required The specific objectives of the team from the Naval Research Laboratory were 1 to provide statistical characterization of the environmental properties, especially the roughness and sediment volume properties 2 measure and model the dispersive behavior of sediment sound speed and attenuation over the 1-400-kHz frequency band 3 conduct in situ manipulative experiments to determine the effects of changing seafloor roughness on high-frequency acoustic scattering 4 determine the effects of biological, geological, and hydrodynamic processes on the spatial and temporal distribution of sediment physical, geotechnical and geoacoustic properties 5 develop predictive empirical and physical models of the relationships among those properties and 6 derive a fundamental understanding of the effects of sediment microstructure porometric and grain properties on fluid flow and geoacoustic properties. During the 60-day experiment NRL divers made 126 dives manipulating seafloor roughness and discrete scatters, measuring seafloor properties and roughness in situ, deploying equipment of the seafloor, and collecting a variety of sediment samples. Preliminary results from SAX04 are presented.
- Radiofrequency Wave Propagation
- Physical and Dynamic Oceanography