Observations of Upper-Ocean Acoustic Propagation Variability and Ambient Soundscape Using Autonomous Surface Vehicles
Abstract
Long-range detection of underwater targets, especially when relying on receivers located in the upper ocean (e.g. sonobuoys, autonomous surface vehicles or arrays operating in the mixed layer or near periscope depth), often relies on acoustic propagation featuresproviding local SNR enhancement such as Convergence Zones (CZs) or Surface and Subsurface Ducts (SSDs). It is therefore critical tobetter understand the fundamental mechanisms affecting the spatial and temporal variability of those features in order to-amongst others-optimize receiver placements in the upper ocean and potentially exploit these features for ASW purposes. For instance, on short spatial and time-scales relevant to acoustic propagation, submesoscale ocean variability (e.g. associated with eddies, fronts, filaments, and/or density compensated temperature and/or salinity anomalies or #spice#) can rapidly modulate the location and size of CZs and SSDs potentially causing detection challenges due to - often unpredictable - low SNR occurrences. Furthermore, quantifying the spatial and temporal variability ambient soundscape variability (e.g. as affected by dynamic ocean processes or bathymetry effects) influencing these upper-ocean measurements, is necessary to provide-amongst others- accurate detection bounds. This 3-year research program will specifically investigate the CZs fluctuations and SSDs instabilities as well as ambient soundscape fluctuations due to the environmental variability occurring in the upper ocean using a suite of both active and passive Acoustical Oceanography (AO) measurements from low to high-frequencies (~100Hz <f<~10kHz) and concurrent physical oceanography (PO) observations of the upper ocean collected from a fleet of Wave Gliders (WGs) across the air-sea interface and the water column (down to ~150m). Approved for public release.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 13, 2025
- Source ID
- N000142512068
Entities
People
- Karim G. Sabra
Organizations
- Georgia Tech Research Corporation
- Office of Naval Research
- United States Navy