Analysis of the Variability of Ship Acoustic Signatures Measured as a Function of Hydrophone Configuration

Résumé

The intensification of maritime traffic implies an increase in underwater anthropogenic noise pollution. It is necessary to describe and quantify the noise generated by maritime traffic, in particular to assess the effects of ship noise on marine animals. Measuring underwater noise radiated by ships is complex, and strongly influenced by measurement conditions. A protocol has been developed to standardize methods for measuring and calculating ship-generated underwater noise (ANSI/ASA S12/64-2009). However, it is often not possible to comply with its many constraints, and each modification is likely to add uncertainty to the final measurement.The Marine Acoustic Research Station (MARS) applied research project (www.projet-mars.ca) is dedicated to understanding and measuring the underwater noise radiated by ships, and proposing appropriate methods for its reduction. An acoustic measurement platform is deployed every year in the Laurentian Channel in the St. Lawrence Estuary, designed to measure the acoustic signatures of ships as closely as possible to the international standard ANSI/ASA S12/64-2009.Since the station's first deployment in June 2021, 101 partner ship passes have been collected, as well as three specially dedicated missions during which the oceanographic research vessel Coriolis II made repeated passes at different distances and speeds. A total of 117 passages on the various measurement antennas have been recorded in 2022. In this way, it will be possible to study the uncertainties and errors in the measurement of the Coriolis II signatures as a function of speed, distance and the number of hydrophones, and to assess the measurement capability of a system as close as possible to the standard by looking at the variability of a ship's signature between antennas of identical configuration.