Improving Icesat Glas Derived Water Surface Elevations Over Lake Van, Türki̇ye

Understanding the impacts of climate change on water resources is crucial for sustainable freshwater management, particularly given that only 0.3% of Earth’s water is accessible surface freshwater. The global decline in operational in situ gauging stations has further highlighted the need for reliable satellite-based alternatives. Although radar and laser altimeters offer valuable data, they require thorough validation to ensure hydrological accuracy. This study assesses the quality of water surface elevation (WSE) derived from the first laser altimetry mission, ICESat, data over Lake Van (Türkiye), the world’s largest soda lake, during its operational period (2003–2009). Initial comparisons revealed root mean square errors (RMSE) ranging from 1.09 to 2.49 m, depending on the satellite track, exceeding values reported in earlier studies. After applying residual corrections, RMSE values were reduced to 0.00–1.25 m, with correlation coefficients increasing to 0.45–0.97. These results confirm the potential of satellite altimetry for monitoring inland water bodies. However, the study also highlights challenges likely to affect follow-on missions such as ICESat-2 and SWOT. The study underscores the importance of developing higher-resolution and more accurate geoid models to improve WSE retrievals, especially for missions requiring stringent precision thresholds.