Characterization of Noise Abatement Systems for Protecting Aquatic Invertebrates and Fishes

Offshore wind energy plays an important role in the future energy supply. But its expansion poses a risk to the marine environment. Especially, during the construction of the foundations high sound pressure levels occur in the water column due to impact pile driving. Noise abatement systems are used to reduce sound pressure levels, primarily to protect marine mammals. However, there is little information on how effective these systems are for protecting aquatic invertebrates and fishes that are sensitive to particle motion. In order to quantify the reduction of sound particle motion due to a noise abatement system a metric is proposed according to the one for sound pressure. For the simple case of a plane wave, the metrics for describing the sound particle motion and sound pressure are compared.