2023_programme: Measurements of Temporal Change in Seafloor Scatter and its Dependence on Environmental Variability

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  • Session: 06. Marine sediment acoustics
    Organiser(s): Megan Ballard, Kevin Lee and Nick Chotiros
  • Lecture: Measurements of Temporal Change in Seafloor Scatter and its Dependence on Environmental Variability
    Paper ID: 1881
    Author(s): Hare Jenna, Lyons Anthony P., Venegas Gabriel R.
    Presenter: Hare Jenna
    Abstract: In the ocean, active sonar systems are used for the purposes of navigation, animal monitoring, object detection, or sea-bed classification. Importantly, the performance of these systems depends on the acoustic properties of the seafloor, which is often assumed to have no temporal dependence. However, daily to monthly variations in near-bottom hydrodynamics and biological activity may affect seafloor properties and, in turn, influence the acoustic response of the seafloor. Previous work has mainly focused on the dependence of seafloor scatter on sediment type, transmit frequency and incidence angle. Thus, questions remain as to the dependence of seafloor scatter on evolving environmental parameters. We are interested in measuring seafloor scatter using high-frequency active acoustic systems to determine the dominant environmental parameters that regulate seafloor scattering on daily to monthly time scales. We analyzed several datasets from a series of experiments containing seafloor scattering measurements from downward-looking sonars deployed in two shallow water locations: a wave-dominated site and a site dominated by strong tidal currents. The experimental set-up consists of a tripod placed on the seafloor equipped with three transducers – operating at 38 kHz, 70 kHz and 200 kHz – and other sensors providing environmental measurements (e.g., temperature, salinity, water depth and significant wave height). Daily, weekly and monthly trends in mean scattered levels and the mechanisms causing their temporal variability are discussed. The results will increase our understanding of the interaction between high-frequency sound and the ocean floor, leading to improved remote-sensing techniques for object detection and continuous seafloor monitoring.
      Download the full paper
  • Corresponding author: Dr Jenna Hare
    Affiliation: University of New Hampshire
    Country: United States
    e-mail:

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