射线理论下的浅海环境噪声场空间相干性分析及海底声学参数反演

基于射线理论,以简化海底模型为基础,获得了浅海噪声场空间相干性在频域上的表示方法,并用于海底声学参数反演。将风关海洋噪声看作分布在无限大平面上的点源,通过计算噪声场垂直方向上的能量分布,进一步获得空间两点噪声场频域相干性表达式。利用数值仿真验证了模型对于不同海底类型的敏感性。并结合噪声场空间两点的频域相干性海上实验数据,反演得到该处海域的底质类型,进一步获得海底声速、密度和声衰减系数。结果表明,反演得到的海底参数与实际情况符合较好,文中提出采用的这种计算方法能够有效的反映海底反射对于噪声场空间相干性的影响,并且可在一定程度上提高反演海底声学参数效率。 

Analysis on spatial coherence of ambient noise and geoacoustic inversion in shallow water

The spatial coherence in frequency domain of ambient noise field in shallow water is calculated based oi1 ray theory and simplified seabed model, and it is used to do geoacoustic inversion. The ambient noise is regarded as many point sources in the infinite plan, and the frequency domain expression of the spatial cohernece is obtained by calculating the energy distribution in the vertical direction of the noise field. Then the sensitivity of model to different seabed is verified by numerical simulation. The sound speed, density and attenuation coefficient of tile seabed are further obtained according to experiment data. The result shows that those parameters get from inversion are in good agreement with actual situation. The method in this paper can effectively reflect the influence of seabed reflection on the spatial coherence of noise field, and can improve the inversion efficiency to a certain extent.