Topographic Reconstruction of Poyang Lake Based on ICESat-2 ATL08 Data

Traditional underwater surveying is often limited by high costs and restricted spatial coverage, while remote sensing-based topographic reconstruction also faces notable challenges. Satellite altimetry offers new opportunities for dynamic lake monitoring, and the integration of multi-source remote sensing technologies has emerged as a vital approach for underwater terrain mapping. Focusing on the Die-shaped Lake within Poyang Lake, this study integrates ICESat-2/ATL08 ground elevation points collected from exposed lakebed areas with multi-temporal water boundaries derived from Landsat-8/9, Sentinel-2 optical imagery, and Sentinel-1 SAR data. Elevation interpolation along receding waterlines during the dry season was employed to densify elevation points within the lake basin, enabling the reconstruction of lakebed topography. A comparison with field-surveyed topography south of the Nanji Bridge revealed a mean deviation of only 0.02 meters, demonstrating that the reconstructed terrain closely matches actual measurements in gently sloping regions. These results provide a novel and effective framework for lakebed topographic mapping, overcoming traditional limitations.