Experiments Shallow Water Acoustic Remote Measurements

SWARM95 map
SWARM95 experiment map

Description

From July 31 to August 5, 1995, Ocean Acoustic Experiments in Support of Shallow Water Acoustic Remote Measurements (SWARM) were conducted by the University of Delaware in conjunction with Woods Hole Oceanographic Institution (WHOI) and the Naval Research Laboratory (NRL). The primary mission was to collect acoustic and environmental data to investigate internal wave phenomena and their influence on acoustic wave propagation. The experiment region consists of a circular region of radius approximately 30 km whose center is located 150 miles offshore northern New Jersey continental shelf into a water column between 60-85 m deep. During the experiment, several Vertical Line Arrays (VLA) were deployed for measuring the acoustic signals generated by a moving source. R/V Cape Hatteras segment of the SWARM95 mission, including individual experiments, equipment employed and deployed.

A Bolts airgun source generates a broadband pulse with a center frequency dependent on the size of an interchangeable air chamber and the amount of air injected into the chamber. Unless noted otherwise all airgun shots were performed at 2000 psi and a 20 $in^3$ chamber was mounted. The figure below shows airgun recorded signals by channel 8 of the WHOI vertical line array

airgun signals SWARM95
Fig. 2. Airgun signals recorded on channel 8 of WHOI vertical line array from JD214 11:49 to 13:49.

Airgun shots and chirp signals were used during the SWARM95 experiment to study the environemtal properties of the site. The Following video shows the modal interference patterns obtained from airguns on August 02, 1995.


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