Directional underwater noise estimation

Estimation of underwater noise – a simplified method

A set of procedures has been developed to allow preliminary estimates to be made of underwater noise and its effects on marine species. They do not require detailed acoustic survey data, either of the site or of the proposed plant. However, they still facilitate the comparison of different project proposals to assist in the optimisation of equipment layout and routing. Noise may be due to speci...

Underwater Ambient Noise

Underwater rain noise : sources, spectra and interpretations

An overview over the most important results obtained over the past of noise produced in water by impacts of single droplets, artificial rain and real rain is presented. Two distinct sources form the major contributors to rainfall produced noise in the sea. The raindrop impact and the pulsations of entrained air bubbles. The impact sound is produced by raindrops of all sizes, while the bubble pu...

Underwater radiated noise from modern commercial ships.

Underwater radiated noise measurements for seven types of modern commercial ships during normal operating conditions are presented. Calibrated acoustic data (<1000 Hz) from an autonomous seafloor-mounted acoustic recorder were combined with ship passage information from the Automatic Identification System. This approach allowed for detailed measurements (i.e., source level, sound exposure level...

Coherence extrapolation for underwater ambient noise.

This paper considers extrapolation of the vertical coherence of surface-generated oceanic ambient noise to simulate measurements made on a longer sensor array. The extrapolation method consists of projecting the noise coherence measured with a limited aperture array into the domain spanned by prolate spheroidal wave functions, which are an orthogonal basis defined by array parameters and the no...