Assessment of Ship-Generated Underwater Noise in the Shallow Lithuanian Marine Klaipėda Port Through Measurements and Modelling

Abstract Mapping of shipping underwater noise purposed for environmental impact assessments and to forecast noise effects on aquatic life incorporate source spectral models. These models published in scientific literature updated regularly, although these may have limitations and may depend on the variables stored in the ship’s automated identification system data, tied to specific locations i.e., ship speeds and their lengths. Regarding these limitations, it is crucial to assess the possibility of model application in the research area. In this paper the results of evaluation of four different noise models in the shallow Lithuanian marine harbor presented. The results acquired using “ECHO-JOMOPANS” model and the updated “Research Ambient Directionality Model” revealed good correlation with measurement results, although these two models have a different dependency on the ships parameters. The benchmarked “ECHO-JOMOPANS” model incorporates the reference spectrum, having the dependency on the sound frequency, ship’s speed, its length and ships database related reference speeds and ships lengths. In contrast, an updated “Research Ambient Directionality Model” is a modification of an original model, having the dependency only on the sound frequency, ship’s speed, and length.