What question did this study set out to answer?

This research aims to understand how low-frequency acoustic signals are affected by the Gulf Stream and seamount interactions.

May 14, 2026

Long range, low frequency source localization across the Gulf Stream front using multiple bottom/surface bounce paths observed on a large aperture vertical array: A Bayesian approach

Key Points

This research aims to understand how low-frequency acoustic signals are affected by the Gulf Stream and seamount interactions.
Two transceiver moorings were deployed across the Gulf Stream, separated by 153 km.
Three consecutive two-minute-long FM sweeps were transmitted at 200–300 Hz every hour.
A Bayesian approach was employed to analyze 23 recorded transmissions and localize the acoustic sources.
Identified 23 acoustic arrivals with varying boundary interactions, between 6 and 17.
Time front arrival pattern indicated 1 s of ducted arrivals followed by 13 s of interacting energy.
High-resolution CTD measurements aided in source localization and understanding propagation physics.

Abstract

The New England Seamounts Calibrated Acoustic Fluctuation Experiment (NESCAFE) is an ongoing experiment to assess how the New England seamounts and Gulf Stream interact to affect low-frequency ocean acoustic propagation. In a spring 2023 pilot study, two transceiver moorings (East and North) were deployed, on either side of the Gulf Stream and away from the seamounts at a range separation of roughly 153 km. The transceivers sent three consecutive two-minute-long up-down 200–300 Hz FM sweeps every hour, and the signals were recorded on upper/lower arrays nominally from 88 to 343 m and 850 to 1093 m. A total of 23 transmissions from the East mooring were recorded on the North mooring before the East mooring failed. The time front arrival pattern shows roughly 1 s of ducted arrivals followed by 13 s of organized bottom/surface interacting energy. Planewave beamforming reveals 23 arrivals with between 6 and 17 boundary interactions. The 23 observations of received angle and travel time are used in a Bayesian approach to localize the source and gain insight into the propagation physics. The localization was aided by high-resolution shipboard Conductivity, Temperature, and Depth (Fast CTD) measurements taken between the moorings, but one month later.

Mark Helpful

Bookmark

Relay