Towards a Noise Map Model for Shallow Waters: Analysis of Propagation Losses Estimation

Propagation in shallow waters is complex and strongly dependent on many factors as the bathymetry, seabed composition and water properties among others. Because of this complexity, there is no standard method to obtain propagation losses in these kind of environments. Present contribution continues previous work in the direction of getting a method to obtain propagation losses of a source placed in shallow water, and so then, being able to calculate the correspondent Source Level. Hydrophone measurements of a calibrated source emitting single tones were made near Limens beach in Pontevedra (North West Spain), a shallow water zone in Ría de Vigo (a drowned river valley). Noise measurements were accompanied with oceanographic sonde (CTD) measures, obtaining salinity, temperature and speed of sound depth profiles close to the measurement zone and also seabed information from a steel core. Same scenario was vastly simulated using dBSea, an underwater noise estimator with 3D bathymetry, in order to evaluate how important the contour variables are (bathymetry, water properties, seabed properties) and how their accuracy affects to the result.Conclusions discuss software and real measurements results and how the discrepancies between them could affect the results of the simulation of a noise map of the area.