Acoustic modeling of a sandy beach for atmospheric sound propagation in a near-shore environment

This article supports a submission presented at the LRSP 18th International Symposium on Long Range Sound Propagation. This work presents the modeling of excess attenuation of a sandy shore and its contribution to the atmospheric sound transmission loss in a near-shore environment. The numerical model uses a parabolic equation method to account for wind and temperature variation with elevation along the propagation path. The surface impedance of a sandy shore is modeled as an equivalent fluid that takes into account the grain size distribution of the sand and its change in water content along the propagation path. The propagation range consists of three segments: over flat water, over wet sand, and over dry sand. Beach acoustic absorption is modeled with an increasing degree of complexity. Acoustic transmission loss predicted by the proposed model is compared with data. It is found that the simplest model of the beach is sufficient to predict sound pressure levels at the shore up to 20 m far from the water edge. However, a more complicated model is needed to capture the acoustic behavior of the beach at locations further away.