Abstract

The main factors affecting the spatial characteristics of surface noise fields are changes in sound speed and sea surface boundary perturbations due to mesoscale ocean phenomena and wind-induced noise, respectively. This study derived the surface noise cross-spectral density sensitivity kernel for sound speed changes and local boundary perturbations and analyzed their effects on cross-spectral density. Numerical results show that the sound speed perturbations of any position in the entire observation plane changes the surface noise cross-spectral density function in surface noise with finite frequency. The cross-spectral density between two receivers in the vertical direction is the most sensitive to the sound speed changes of the region between two receivers. Additionally, the influence depends on the relationship between the wavelength of sound wave and the distance of two receivers. Scattering on the surface boundary perturbation would lead to fluctuations in the cross-spectral density function. When the boundary perturbation along the horizontal direction is distant from two receivers, the cross-spectral density sensitivity kernel for surface scattering oscillates, and the influence of boundary perturbation on the cross-spectral density function gradually weakens. Finally, the period of the cross-spectral density sensitivity kernel oscillations is a half wavelength of the sound wave.

中文翻译：

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表面噪声场中的互谱密度敏感核

摘要

影响表面噪声场空间特性的主要因素分别是中尺度海洋现象和风致噪声引起的声速变化和海面边界扰动。这项研究推导了表面声波频谱密度敏感度内核，用于分析声速变化和局部边界扰动，并分析了它们对频谱密度的影响。数值结果表明，在整个观测平面内，任何位置的声速扰动都会改变表面噪声在有限频率下的表面噪声互谱密度函数。垂直方向上两个接收器之间的互谱密度对两个接收器之间区域的声速变化最敏感。另外，影响取决于声波的波长和两个接收器的距离之间的关系。表面边界摄动上的散射将导致交叉光谱密度函数的波动。当沿水平方向的边界扰动远离两个接收器时，用于表面散射的跨谱密度敏感度内核发生振荡，并且边界摄动对跨谱密度函数的影响逐渐减弱。最后，互谱密度敏感核振荡的周期是声波的一半波长 当沿水平方向的边界扰动远离两个接收器时，用于表面散射的跨谱密度敏感度内核发生振荡，并且边界摄动对跨谱密度函数的影响逐渐减弱。最后，互谱密度敏感核振荡的周期是声波的一半波长 当沿水平方向的边界扰动远离两个接收器时，用于表面散射的跨谱密度敏感度核振荡，并且边界摄动对跨谱密度函数的影响逐渐减弱。最后，互谱密度敏感核振荡的周期是声波的一半波长。