南海深海风生噪声特性分析及其噪声源模型修正

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

基于2015年秋季南海深海区域43天的观测噪声与同步风速预报数据,研究南海风占主导海洋环境噪声风关特性,并对风生噪声源级公式进行修正。本地风速在3〜14 m/s范围内变化时,在频段0.5〜1.28 kHz,噪声强度近似正比于风速对数的2倍。据此关系,获得不同风速条件下的风生噪声谱级。将Harrison风生噪声源级公式和海面噪声传输模型结合,构建深海风生噪声数值计算模型,通过求取最优的风生噪声源级公式系数项,使得在风占主导频段和风速范围内实验谱级与数值结果误差平方和最小,对Harrison风生噪声源级公式进行修正,并使其适用频段范围拓宽两倍。最后,利用南海其它区域实验数据检验模型的适用性,结果表明,模型预报噪声级与实验值吻合度较高,可供预报南海风生海洋环境噪声级实际应用参考。

Based on the long-term observation noise and synchronous wind speed data in the deep water of the South China Sea in autumn 2015,the characteristics of the wind-dominated ambient noise are analyzed and the source level models at different wind speeds are modified.The results of data processing show approximate quadratic noise-wind speed dependence in frequency range of 0.5-3.2 kHz when the local wind speed exceeds 3 m/s.The ambient noise spectrum levels averaged in the different wind speeds are obtained based on the relationship.Based on ray theory,a numerical modeling of ambient noise field in deep water is established.The wind source level formula is revised by minimizing the deviation between experimental noise spectra and numerical results at the wind-dominated frequency band,and the applicable frequency band is expanded to twice ford.In the end,the revised model is verified by comparing the forecasted noise spectra with the experiment data measured from another site in 2016.The model might be used to forecast the ambient noise level in the South China Sea from marine meteorological forecast.