Evaluating the Accuracy of Global Bathymetric Models in the Red Sea Using Shipborne Bathymetry

Abstract

Global bathymetric models derived from satellite altimetry are important for studying the Earth’s oceans. However, the accuracy of these models can vary across different geographic regions. This study evaluates four widely used global bathymetric models ETOPO 2022, GEBCO 2023, SRTM15 + V2.5.5, and DTU18BAT in the Red Sea using 268,071 reference shipborne bathymetric measurements. The analysis compares the models’ depth estimates to the shipborne measurements across different depth ranges between 0 and 3000 m. The results show that overall, the GEBCO 2023 model provides the highest accuracy with the lowest standard deviation of 43.774 m and root mean square error of 43.929 m relative to shipborne data. The ETOPO 2022 model ranks second in accuracy with a standard deviation of 45.316 m and root mean square error of 45.345 m. The frequency distribution of residuals indicates that GEBCO 2023 and ETOPO 2022 models have the most precise depth predictions concentrated tightly around zero difference, while SRTM15 + V2.5.5 and DTU18BAT ones show broader spreads. There is no systematic depth over or under-predictions. Finally, the GEBCO 2023 and ETOPO 2022 models show good accuracy in the Red Sea, outperforming SRTM15 + V2.5.5 and DTU18BAT.