Comparative Analysis of Satellite-Based Elevation Models and High-Resolution Terrain Data for Coastal Flood Risk Assessment in the Red Sea Region

This research conducts a comparative analysis of three Digital Elevation Models—developed High-Resolution Digital Elevation Model (HRDEM) as a reference, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), and Shuttle Radar Topography Mission (SRTM)—across the study region from Suez to Hurghada. Initially, elevation and slope characteristics are evaluated using elevation difference statistics, revealing that ASTER and SRTM exhibit broader elevation ranges and more rugged topographical features than the reference DEM. Subsequent statistical analysis identifies notable outliers, with ASTER and SRTM datasets showing high slope values that may necessitate additional quality assessments. Further examination using skewness and kurtosis metrics indicates a symmetrical distribution, highlighting a decline and slope bias toward lower values accompanied by significant outliers. Elevation differencing was then performed to generate error maps, uncovering significant discrepancies between ASTER and the reference, as well as between SRTM and the reference. Root Mean Square Error (RMSE) values demonstrate notable variations between ASTER and SRTM relative to the reference DEM, with the ASTER-reference comparison indicating a marginally reduced mean elevation bias compared to the SRTM-reference. ASTER and SRTM datasets exhibit significant skewness and kurtosis, signifying pronounced terrain fluctuations and noise. Ultimately, HRDEM presents a more balanced and reliable representation of the terrain, underscoring its reliability as a reference model for precise terrain modelling and the necessity for accurate terrain modelling while using ASTER and SRTM datasets as their intrinsic biases and elevated kurtosis can adversely affect geomorphometric analysis, coastal flooding assessments, and risk evaluations.