ACOUSTIC TRANSMISSION LOSS MEASUREMENTS IN QUEEN CHARLOTTE BASIN

摘要

A transmission loss experiment was carried out during the winter in south Hecate Strait using a small airgun array source. Airgun pulses were recorded at horizontal receiver ranges between 20 m and 10 km using a bottom-mounted hydrophone recorder. Transmission loss values were computed by subtracting measured source levels from received sound levels in 1/3-octave bands. Transmission loss data were compared to predictions from a parabolic-equation (PE) sound propagation model coupled with an airgun array source level model. The measured transmission loss was characteristic of cylindrical spreading, with very little additional loss attributable to non-geometric terms. Mid-frequency (100-400 Hz) sound propagation was found to be best supported by the environment. The PE model predictions showed good agreement with the experimental data.