New England shelf break acoustic (NESBA) experiment: Seabed analysis

The NESBA signals and noise experiment was conducted in April–May, 2021. The goal of the experiment was to assess the potential for improving sonar prediction through enhanced environmental awareness. In this talk, an overview of the experiment will be presented along with a description of the environmental conditions. Extensive measurements and modeling were used to help characterize the complex oceanography and seabed. The study region had water depths that varied from 70 m to 2000 m and included a diversity of seabed types and sub-bottom layering. Along the shelf break, there are regions where the seabed sub-bottom layering is particularly intricate. This talk will focus on the NESBA sub-goal of determining the properties of the seabed using passive sensing from two drifting, vertical hydrophone arrays. One array had 16 hydrophones spaced at 1 m and the other had 32 hydrophones with spacing of 0.1875 m. The seabed characterization is based on array processing techniques using the wind generated surface noise. Results will be presented for seabed characterization from several sites in the NESBA region with discussion on the potential impact on acoustic propagation. [Work supported by the Office of Naval Research.]