Enhancing Backscatter Data Processing Through Sound Speed and Salinity Proxies

This study investigates the application of multibeam echosounder (MBES) systems, primarily to improve the accuracy of seafloor classification by improving the standardization of backscattering data. The main goal was to refine the estimation of in-situ water temperatures using sound wave propagation speeds and to evaluate the influence of environmental factors such as salinity on the absorption coefficients applied in backscatter data interpretation. To evaluate the accuracy of water temperature estimation using empirical sound velocity formulas, SVP (Sound Velocity Profile) and CTD (Conductivity, Temperature, and Depth) measurements were taken at a depth 120 m off the southeastern coast of South Korea, together with MBES survey. The findings show that field measurements using CTD sensors can effectively calibrate and validate empirical sound velocity models, ensuring more accurate estimations of water temperature and salinity impacts on sound transmission. Results indicate that the ability to effectively estimate on-site water temperature using transmission speed and average salinity derived from existing data enhances the accuracy of the existing MBES data. Significant fluctuations in ARC (angular response curve) patterns have been observed in regions with steep seafloor slopes, indicating that topographic variations have a substantial impact on acoustic backscattering. This study highlights the necessity of integrating in-situ environmental corrections to adaptively manage variability in seafloor mapping, enabling robust interpretations of marine topography.