Seafloor characterization of the Historic Area Remediation Site using angular range analysis

Angular Range Analysis (ARA) is a physics-based approach to acoustic remote seafloor characterization. In order to better understand the capabilities and limitations of this technique, ARA analyses were performed on multibeam sonar data collected at the Historical Area Remediation Site, an area with high spatial variability. The remotely derived results were compared to grain size information derived from grab samples and Sediment Profile Imaging. Uncertainties in the determination of mean grain size from ground truth were identified and when possible quantified. ARA proved to be an effective remote sensing tool at a regional scale in its main operational mode that has a spatial resolution limited to half-swath width of the sonar and to thirty pings. When the seafloor is heterogeneous within half-swath width of the sonar, textural segmentation of the backscatter mosaic allows the definition of themes out which ARA solutions can be calculated, improving the correlation with ground truth