2025_programme: Dissecting Acoustic Arrival Structures in the Beaufort Sea

• Day: June 20, Friday
    Location / Time: D. CHLOE at 08:30 - 08:50
• Last minutes changes: -
• Session: 02. Acoustics in polar environments
  Organiser(s): Espen Storheim, Lora van Uffelen, Oskar Glowacki
  Chairperson(s): Lora Van Uffelen
• Lecture: Dissecting Acoustic Arrival Structures in the Beaufort Sea [Invited]
  Paper ID: 2264
  Author(s): Jessica Desrochers, Luis Pomales Velazquez, Lora Van Uffelen
  Presenter: Lora Van Uffelen
  Abstract: Over the past few decades, the water column in the Canada Basin has evolved resulting in a sound speed profile that includes a strong subsurface duct between 100- and 300-meters depth, known as the Beaufort Duct, which enables long-range acoustic propagation across the Beaufort Sea. This research looks at the predicted acoustic arrivals in this region using oceanographic profile data collected by two Seagliders in the summer of 2017. These vehicles also recorded transmissions from active acoustic sources moored within the duct. Broadband acoustic modeling was performed using a bandwidth of 100 Hz centered at 275 Hz and a source depth of 180 meters based on the active source parameters in the experiment. Both the recorded acoustic data and the modeled time fronts show a prominent peak acoustic arrival prior to the final cutoff. This marks the beginning of the Reverse Geometric Dispersion (RGD) feature, in which a reversal of mode arrival dispersion occurs. This feature is made up of a segment of the time front where lower order modes arrive first, layered on top of acoustic arrivals following a typical deep water time front arrival pattern, in which the higher order modes arrive first. The modeled acoustic arrival structure is explored using ray trace and normal mode acoustic propagation models by breaking down the time front arrival structure into three distinct sections and relating these sections to acoustic energy pathways for the unique sound speed profile observed in this region.
• Corresponding author: Ms Jessica Desrochers
  Affiliation: University of Rhode Island
  Country: United States