2025_programme: Underwater measurements of sound particle motion for model validation

• Day: June 17, Tuesday
    Location / Time: C. THALIA at 08:50 - 09:10
• Last minutes changes: -
• Session: 23. Underwater noise modelling and measurements
  Organiser(s): David Barclay, Martin Siderius
  Chairperson(s): David Barclay, Martin Siderius
• Lecture: Underwater measurements of sound particle motion for model validation
  Paper ID: 2136
  Author(s): Timo Constantin Gaida, Christ de Jong, Bas Binnerts, Erwin Jansen, Victor O. Oppeneer
  Presenter: Timo Constantin Gaida
  Abstract: Underwater sound maps displaying the sound pressure field in the sea are commonly used to investigate the state of the underwater environment. However, most fishes and aquatic invertebrates are predominantly sensitive to particle motion. Model benchmarking has already verified the applicability of existing models to calculate sound particle motion in addition to sound pressure. Additionally, the models can be validated via comparison with experimental data. As part of the EU Horizon 2020 project SATURN, an experiment was set up to measure sound particle motion in the Dutch North Sea in May 2022. A rig measuring sound pressure as well as sound particle acceleration in three orthogonal directions, between 20 Hz and 4 kHz, was placed on the seabed at 13 m water depth. The rig collected data from the sound produced by a controlled airgun source deployed from a small boat at various distances (50 to 1600 m) and directions from the rig. From the measured airgun source level and rig measurements, the sound pressure propagation loss (PL) and sound particle velocity propagation loss (PVL) were derived. Comparison with the results of RAM (parabolic equation model) calculations shows that the average model-data differences for PL and PVL are generally within ±6 dB for the decidecade bands from 100 Hz to 1 kHz, and substantially higher than modelled below 100 Hz. Above 1 kHz, the difference increases with increasing range. One obvious cause for the model-data differences is the uncertainty in sediment properties used in the geo-acoustic modelling. This field campaign illustrates challenges of measuring and modelling sound particle motion and adds further guidance for future studies.
• Corresponding author: Dr Timo Constantin Gaida
  Affiliation: TNO
  Country: Netherlands