Validating shipping noise simulations for the Red Sea using field measurements

The Red Sea is increasingly impacted by underwater radiated noise (URN) from intense commercial shipping activity. This study evaluates the accuracy of a physics-based noise modeling framework in this environment by comparing modeled sound pressure levels (SPLs) with in situ acoustic measurements. Broadband (40-150 Hz) shipping and wind-driven noise was modeled using Automatic Identification System (AIS) data, the Hildebrand wind noise model, and parabolic equation-based acoustic propagation (RAM), with source levels parameterized for each vessel. Six autonomous acoustic recorders were deployed at two locations (King Abdullah Economic City and Al Fahal), covering both shallow and deep sites during two 12-day periods in summer and winter. Model predictions were compared against measured SPLs in both time and frequency domains. The results demonstrate strong seasonal and spatial variability in underwater noise levels, with modeled median SPLs closely matching observations at most sites. The analysis reveals that ship traffic is the dominant source of underwater noise, while other sources such as winds that were explicitly accounted in the simulations, showed a minimal contributions. Additionally, the findings suggest a seasonal influence on propagation conditions. Despite the inability to model certain biological or other non-shipping noise sources, the validation confirms that the model robustly captures dominant trends in low-frequency noise. The findings support the use of this modeling approach as a reliable basis for regional noise mapping and future marine spatial planning and mitigation efforts in the Red Sea.