Underwater acoustic recordings of six Floating Production Storage and Offloading (FPSO) vessels moored off Western Australia are presented. Monopole source spectra were computed for use in environmental impact assessments of underwater noise. Given that operations on the FPSOs varied over the period of recording, and were sometimes unknown, the authors present a statistical approach to noise le...

Acoustic Daylight is a new technique for creating pictorial images of undersea objects from the acoustic illumination provided by the ambient noise field. As in conventional photography, the directionality of the illumination affects the contrast in the image through the shadows that are cast. Three aspects of the directionality, or anisotropy, of ambient noise in the ocean are discussed in thi...

In this paper approach for the underwater sensor network based on the blue-green laser has been proposed. We describe the application of the underwater sensor network in the undersea exploration, and discuss the difficulties in the traditional underwater sensor network. A basic of prototype of underwater laser sensor network has been advanced, which include the architecture of laser network and...

We propose a new method for practical non-Gaussian and nonstationary underwater noise modeling. This model is very useful for passive sonar in shallow waters. In this application, measurement of additive noise in natural environment and exhibits shows that noise can sometimes be significantly non-Gaussian and a time-varying feature especially in the variance. Therefore, signal processing algori...

1. To demonstrate theoretically emergence of the deterministic Green’s functions (GFs) from noise sources distributed in a volume and on boundaries in inhomogeneous, fluid-solid environments with dissipation. 2. To investigate a relation between the deterministic GFs and a two-point correlation function of noise in a low-frequency regime where stationary-point arguments become inapplicable. 3. ...

Abstract Distributed acoustic sensing (DAS) is an ideal tool for ambient noise tomography owing to the dense spatial measurements and ability continuously record in harsh environments, such as underwater. Although fine sampling of DAS facilitates imaging small-scale lateral velocity heterogeneities, efforts relying on dispersion-based are hampered by underlying premise negligible variations acr...

[1] Interstation cross correlations of ambient seismic noise from 1 year of continuous data at periods between 6 and 50 s are used to study the origin of the ambient noise using stations located in Europe, southern Africa, Asia, and three regions within North America. The signal-to-noise ratios (SNR) of Rayleigh waves for positive and negative correlation time lags at periods of 8, 14, 25 and 5...

Underwater noise caused by impulse pile-driving during the installation of offshore foundations is potentially harmful to marine life, especially marine mammals. In Germany the regulation authority (BSH) set following limit values: (i) Sound Exposure Level (SEL) = 160 dB (re 1 μ Pa 2 s) and (ii) Peak Level (LPeak) = 190 dB (re 1 μ Pa) which must be complied with at a distance of 750 m to the co...

There are numerous studies showing that there is a constant increase in the ocean ambient noise level and the ever-growing demand for developing algorithms for detecting weak signals in ambient noise. In this study, we utilize dynamical and statistical complexity to detect the presence of weak ship noise embedded in ambient noise. The ambient noise and ship noise were recorded in the South Chin...