Acoustic characteristic measurement model for ocean ambient noise sources

There is a need to reduce fluctuations in the measured values obtained from receivers in shallow sea environments caused by the complex sound propagation process in such environments. With this aim in mind, and on the basis of energy conservation, a sound field model is proposed to analyze the deterministic relationship between shallow sea noise fields and noise sources by using the sound energy flow density. This approach is extended to a sound field model based on the K/I surface noise source model in the context of normal wave theory. The incoherent cross terms are eliminated by the orthogonal completeness of each mode of the normal wave, which shows that the theoretical approach proposed in this paper can eliminate the interference caused by interface reflection and multipath effects. An analytical formula for the energy attenuation coefficient is given. Using experimental data from a shallow water area in the South China Sea, the proposed approach is applied in different sound source scenarios, and it is found that it effectively reduces noise fluctuations. The acoustic energy flux density can be used to provide an accurate representation of temporal variations in noise sources. It is found that increasing the receiver array length leads to decreases in the noise standard deviation and mean value and thus reduces the degree of fluctuation.