2006 Strategic Environmental Assessment SEA7 Technical Report - Underwater Ambient Noise (NE Atlantic west of Scotland)

This report on underwater noise is a contribution to the Strategic Environmental Assessment (SEA7) conducted by the Department of Trade and Industry (now Department of Energy and Climate Change). This report initially gives a general introduction to underwater ambient noise and the underlying mechanisms that generate sound. The report then identifies a number of sources of underwater acoustic noise, describes the characteristics of the noise including frequency content, levels and variability, and also identifies the current state of knowledge on each source. In all cases the sources are considered in the context of the SEA 7 area. Mechanisms that can modify the ambient sound levels are described. The dominant noise sources in the SEA 7 area are identified. Recommendations are then made for the methodology to be used to obtain meaningful characterisation of noise levels in order to establish baseline levels. The report then goes on to present an analysis of measured ambient noise data in the SEA 7 area, model predictions of spectrum levels, and compares the measured and modelled data.