Seasonal Characterisation of Sonar Performance for Effective Underwater Surveillance in the Marmara Sea

This study analyses sonar performance for underwater object detection in four regions of the Marmara Sea, using oceanographic data from the Turkish Naval Forces and open source datasets. Simulations were conducted with LYBIN acoustic modelling software across four seasons (January, May, July and October), evaluating variable-depth sonar (VDS) and hull-mounted sonar (HMS) systems for coverage and detection performance. Results identified optimal sonar coverage zones, highlighting seasonal impacts on propagation, with temperature and salinity fluctuations directly influencing performance. Seasonal stratification in the Marmara Sea generates surface ducts and shadow zones that strongly constrain HMS performance, while VDS consistently mitigates these effects. Simulations demonstrate that VDS reduces shadowed areas by 25% across all seasons and regions, extending reliable detection ranges compared with HMS. The study provides a foundation for designing efficient underwater surveillance systems in the Marmara Sea, offering insights for optimising operational strategies. Future research should explore diverse marine conditions and sonar configurations to enhance detection capabilities.