Remote Sensing Technique for Geoacoustic Characterization of Heterogeneous Marine Sediments

摘要

The long term goal of this research is to develop an improved physics-based technique for remote quantification of seafloor geoacoustical properties. The specific scientific tasks of this project were: (1) to develop inversion algorithms for estimating the sediment grain size distribution of coarse fractions in sandy sediments based on a recently developed inclusion scattering' model, (2) to test these algorithms using the SAXO4 scattering data, and (3) to provide ground truth for such tests by direct measurements of the grain size distribution in the available SAXO4 sediment samples and cores. The tasks were accomplished. An algorithm for scattering data inversions was developed based on a parameterization of the grain size distribution using power law approximations in given intervals of sizes. The algorithm allows inversions of the level and power exponent of the size distribution in each interval. To provide ground truth for testing the algorithm, 13 sediment samples taken at the SAXO4 site were analyzed. Sand grains and shell particles were separated and their number, weight and shape factor were measured in each size interval. It was demonstrated that the SAXO4 acoustic scattering data inversion based on the developed algorithm provides a qualitative fit to the ground truth data.