Determining the directionality of anthropogenic noise using an underwater acoustic vector sensor: a case study in a Norwegian fjord

Abstract

Sources of anthropogenic noise in the ocean have temporal and directional characteristics. Characterizing the soundscape requires identifying the directionality of the sources of noise in addition to the non-directional sound pressure. An underwater acoustic vector sensor (AVS) can be used to provide the directionality of incoming noise, and the concomitant sound pressure. We present an analysis of measurements from an AVS deployed in a Norwegian fjord in which there is frequent commercial ship traffic. We assessed the directionality of various known and unknown noise sources and used it to interpret the associated sound pressure. The fjord soundscape consists of time-varying noise directionality and intensity from anthropogenic sources, especially shipping activity. This case study highlights the benefits of using information from an AVS to assess noise directionality in a soundscape.