Low to mid-frequency scattering and propagation in the New England Seamount Chain
Abstract
The work presented in this proposal would further the goals of both the Office of Naval Research (ONR) Task Force Ocean (TFO) Program and the ONR Ocean Acoustics Program by significantly broadening acoustic measurement activities in ONR sea trials, advancing deep-water acoustics research in scattering, propagation, and ambient noise, and increasing the Navy#s talent pool through supporting student research. At-sea experimental data collection would be performed during the upcoming New England Seamounts Acoustics 2024 (NESMA24) trial, as well as another sea trial as directed by ONR. Deep-water scattering, propagation, and ambient noise within the New England Seamount region would be investigated to characterize this region in a manner that may allow extrapolation to similar regionsaround the globe. Finally, this funding would support operations and maintenance of the Three Octave Research Array (THORA), which is maintained and operated by the Pennsylvania State University, Applied Research Laboratory (PSU-ARL), but funded by and operated at the discretion of the ONR.Experimental measurements will include using PSU-ARL#s recently acquired THORA acquisition system, in conjunction with several experimental sources and a glider-based line array system, to examine scattering and propagation within the New England Seamounts region. Acoustic sources will include a low to mid-frequency (0.05 # 4.5 kHz) towed source operated by William Hodgkiss of Scripps Institute of Oceanography (SIO), a towed mid-frequency (1.5 # 6.5 kHz) source operated by PSU-ARL, Signal, Underwater Sound (SUS) charges organized by The University of Rhode Island (URI) (James Miller), and several autonomous moored sources placed by Woods Hole Oceanographic Institute (WHOI) and SIO. Additionally, tandem line-array receiver operations will be orchestrated between the THORA and URI#s glider-base line array system (Thayer Mahan) that is also planned for deployment during the NESMA24 trial. The overarching goal of these collaborative measurements is to acoustically characterize the influence of large seamounts and theGulf Stream (GS) in this region.In addition to experimental work, this funding will support basic research and two graduate students. PSU-ARL has three closely related topics of interest: 1) characterizing low to mid-frequency scattering from seamount flanks and the importance of 3D acoustics, 2) analyzing and modeling the influence of seamount bathymetry and roughness on deep-water acoustic shadow and convergence zones, and 3) examining the directionality and statistics of ambient noise near seamounts. Active measurements for these investigations will include monostatic and bistatic source-receiver geometries and cover a wide band of frequencies (0.05 # 6.5 kHz) using two towed line arrays (PSU-ARL#s and URI#s). The angular resolution of these line arrays will allow measurement of the horizontal breadth and directionality of acoustic signals at high signal-to-noise ratio (SNR), while the ship-based PSU-ARL array will allow measurements over a very large experimental region. Passive noise measurements will cover the 0.05 to 12 kHz band.In addition to the entities directly involved with these collaborative research studies, PSU-ARL will share collected data with other entities as directed by ONR.Approved for Public Release.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Nov 08, 2024
- Source ID
- N000142412425
Entities
People
- Chad Smith
Organizations
- Office of Naval Research
- Pennsylvania State University
- United States Navy