Empirical observations of significant wave height and atmospheric acoustic transmission loss in a near-shore environment

Sound is influenced by meteorological conditions as it travels, which can have profound effect on transmission loss over long ranges. Conditions, such as wind speed, wind direction, and temperature, are primary atmospheric variables affecting transmission loss. At longer ranges, the surface roughness of the water is also an important factor to consider. Significant wave height is a typical metric to characterize the water surface roughness. A June 2024 field measurement campaign was completed in the Pamlico Sound adjacent to the East Carolina University Outer Banks campus. Measurement of meteorological conditions and concurrent acoustic transmission losses were performed over water only at ranges from 250 m to 2 km. A buoy that records three-dimensional wave motion was incorporated into the measurement process and deployed between the acoustic source and receiver array. The record of wave dynamics allows for the calculation of significant wave height. The approach to synchronizing wave height measurements to the acoustic measurements is discussed. Results are presented to show how water surface roughness relates to measured transmission loss.