2019_programme: MODELING AND MEASUREMENT OF ACOUSTIC PROPAGATION PATHS FROM FIXED SOURCES TO MOBILE RECEIVERS IN THE CANADA BASIN

• Session: 09. Acoustics in polar environments
  Organiser(s): Tegowski Jaroslaw
• Lecture: MODELING AND MEASUREMENT OF ACOUSTIC PROPAGATION PATHS FROM FIXED SOURCES TO MOBILE RECEIVERS IN THE CANADA BASIN
  Paper ID: 833
  Author(s): Van Uffelen Lora, Webster Sarah, Nguyen An, Worcester Peter, Dzieciuch Matthew
  Presenter: Van Uffelen Lora
  Presentation type: oral
  Abstract: As part of the Canada Basin Acoustic Glider Experiment (CABAGE), two Seagliders equipped with temperature, conductivity and pressure sensors, acoustic recorders, and acoustic Doppler current profilers were deployed in the Canada Basin. This was performed in conjunction with the 2016-2017 Canada Basin Acoustic Propagation Experiment (CANAPE), a large-scale acoustic tomography experiment in the Beaufort Sea. The Seagliders received acoustic transmissions from moored (~250 Hz) acoustic sources at ranges up to 480 km. Sources were moored at approximately 175 m depth within an acoustic duct (sometimes referred to at the Beaufort Duct), which is present in the Canada Basin due to the presence of Pacific Winter Water, enabling acoustic transmission to long ranges. \n\nTo model the acoustic propagation environment, an estimate of the sound-speed is derived from temperature and salinity measurements on the Seagliders where data are available. Parabolic equation predictions are compared with measured acoustic data. Acoustic predictions are also made using a range independent sound-speed profile derived from World Ocean Atlas climatological data and range-dependent sound-speed derived from a regional adjoint-based state-estimate, the Arctic Subpolar gyre sTate Estimate (ASTE). ASTE is a medium resolution data-constrained ocean-sea ice estimate that covers the years 2002-2017. The observation backbone in ASTE includes satellite sea ice concentration and thickness, ITP and other CTD and moored data in the Arctic basin interior, and hydrography and velocity at important gateways into the Arctic Ocean and its marginal seas. The fit of ASTE to the observations was achieved through linear least-square minimization of a misfit function subject to strict constraint of the model conservation laws. As such ASTE is dynamically consistent.\n\nThe ASTE model provides a temporally- and spatially- varying estimate of the acoustic propagation environment throughout the deployment timeframe. Initial propagation results show good agreement with received acoustic data on the gliders.
• Corresponding author: Prof Van Uffelen Lora
  Affiliation: University of Rhode Island Department of Ocean Engineering
  Country: United States
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