Modelling the coastal, ambient, marine noise field in space, time and frequency

The objective of this work is to model the natural ambient noise level in coastal regions based on local environmental forcing and propagation conditions. 546 continuous hours of noise were recorded between April 15 and May 7, 2018 in Sooke Inlet, British Columbia, a coastal, shallow-water region with complex bathymetry and diverse surface traffic. Optimal 1-hour lagged correlation between raw wind speed and hourly minimum sound pressure level (dB re 1 μPa/Hz) is computed as a function of frequency. Low frequencies (10–500 Hz) are characterized by poor correlation due to flow noise and near continuous shipping and small vessel traffic. Mid-frequencies (0.5–10 kHz) show increasing correlation with the shift from ship to wind dominated forcing. High frequencies (10 kHz +) show good correlation with wind. The empirically derived relationship between noise and wind speed is used to validate a predictive ambient noise model, driven by local weather and oceanographic conditions, an acoustic transmission loss model, and a wind to wave energy model. The noise model’s sensitivity to temporal and spatial resolution of environmental and forcing data, and knowledge of bathymetry and bottom type will be quantified with the objective of model portability to other coastal regions.The objective of this work is to model the natural ambient noise level in coastal regions based on local environmental forcing and propagation conditions. 546 continuous hours of noise were recorded between April 15 and May 7, 2018 in Sooke Inlet, British Columbia, a coastal, shallow-water region with complex bathymetry and diverse surface traffic. Optimal 1-hour lagged correlation between raw wind speed and hourly minimum sound pressure level (dB re 1 μPa/Hz) is computed as a function of frequency. Low frequencies (10–500 Hz) are characterized by poor correlation due to flow noise and near continuous shipping and small vessel traffic. Mid-frequencies (0.5–10 kHz) show increasing correlation with the shift from ship to wind dominated forcing. High frequencies (10 kHz +) show good correlation with wind. The empirically derived relationship between noise and wind speed is used to validate a predictive ambient noise model, driven by local weather and oceanographic conditions, an acoustic transmission loss mo...