Characterization and source level modeling revision of the wind-generated ambient noise in South China Sea

Based on 43 days observation noise and synchronous sea surface wind speed data in the deep-water area of the South China Sea in autumn 2015,the characteristics of the windgenerated ambient noise are analyzed and the source level models at different wind speeds are modified.The results of data processing show that noise intensity is approximately proportional to twice the logarithm of wind speed in frequency range of 0.5-1.28 kHz when the local wind speed changes within the range of 3-14 m/s.The ambient noise spectrum levels averaged in different wind speeds are obtained based on this relationship.By combining the Harrison windgenerated noise source-level formula with the sea surface noise transmission model,a numerical modeling of ambient noise field in deep-water is established.By minimizing the deviation between experimental noise spectrum levels and numerical results at the wind-generated frequency band,the optimal wind-generated noise source-level formula coefficient term is obtained.Then,the wind source level formula is modified,and the applicable frequency band is expanded twofold.In the end,the modified model is verified by comparing the forecasted noise spectrum levels with the experiment data measured from another site in 2016.The model may be used to forecast the ambient noise level in South China Sea from marine meteorological forecast.