2025_programme: On the convergence rate of ocean noise

• Day: June 17, Tuesday
    Location / Time: C. THALIA at 09:50 - 10:10
• Last minutes changes: -
• Session: 23. Underwater noise modelling and measurements
  Organiser(s): David Barclay, Martin Siderius
  Chairperson(s): David Barclay, Martin Siderius
• Lecture: On the convergence rate of ocean noise
  Paper ID: 2334
  Author(s): David Barclay, Ernst Uzhansky
  Presenter: David Barclay
  Abstract: The convergence (or emergence) time required to estimate the second order statistics of an underwater noise process within a predefined uncertainty can depend on the noise generation process and the ocean environment. This characteristic time scale prescribes the length of acoustic pressure time series required to accurately estimate the auto and cross-correlation, the power and cross-spectrum, and the coherence. Since the coherence is a normalized quantity, it depends solely on the geometry of sources and receivers, and the structure of the ocean environment and its boundaries. The stationarity of the sound generation mechanism (for example, the wind speed) does not play an important role in the stationary of the coherence, unlike the power spectrum. As a result, the coherence provides an excellent theoretical (and experimentally verified) reference against which the convergence time can be calculated. Using a variety of ambient noise data sets captured from mobile and stationary receivers, different noise processes (wind and flow noise) give rise to different coherence convergence times. For wind-driven wave generated noise at the sea surface, there is a weak dependence of the convergence rate and the effective area of the ocean's surface observed.
• Corresponding author: Dr David Barclay
  Affiliation: Dalhousie University, Dept of Oceanography
  Country: Canada