Accuracy Assessment of the Antarctic Digital Elevation Model Based on the ICESat-2 Elevation Data

Antarctic Digital Elevation Models (DEMs) provide critical topographic support for polar scientific expeditions and enable the estimation of melt pond volumes. However, conventional ground calibration methods face implementation challenges in extreme Antarctic environments. Spaceborne Light Detection And Ranging (LiDAR) effectively addresses this limitation by directly acquiring high-precision surface elevation data. ICESat-2, a next-generation laser altimetry satellite, features an exceptionally small laser footprint spacing of merely 0.7 m. The elevation data products of ICESat-2 over the Antarctic ice sheet achieve centimeter-level accuracy using the Reference Elevation Model of Antarctica (REMA) source data. This study first validated the elevation accuracy of the ICESat-2 ATL06 (Advanced Topographic Laser Altimeter System Land Ice Height) data products using the IDHDT4 (IceBridge HiCARS Depth Digitizer Time Series, Version 4) data from the 2015 Operation IceBridge campaign of NASA in the McMurdo Dry Valleys region and mitigated disturbances from cloud cover, snowfall, and other factors through a quality control algorithm. Building upon this validation, this study systematically assessed the elevation accuracy of the 32 m resolution REMA DEM across selected low-ablation regions of the Antarctic ice sheet, delineated according to Antarctic drainage basin boundaries, using the ATL06 data as a reference. Results showed that REMA DEM achieves submeter accuracy (comparable to laser altimetry precision) in flat terrains with slopes below 5°, with a Root-Mean-Square Error (RMSE) of 0.72 m and a Mean Absolute Error (MAE) of 0.31 m. For moderate slopes of 5°–10°, the RMSE and MAE increased to 1.91 and 1.06 m, respectively; meanwhile, slopes of 10°–15° yielded values of 2.30 m (RMSE) and 1.57 m (MAE). Even at steeper slopes of 30°, the elevation error remained controlled, with the RMSE not exceeding 3.5 m. This study further quantified the impact of ground track orientation relative to slope aspect and seasonal variations. Track-aspect angles perpendicular to slopes intensify errors (e.g., RMSE increases by 170% at a slope of 15°), whereas seasonal differences in elevation errors remain minimal (i.e., <5%). The validation framework demonstrates the robustness of REMA DEM across diverse Antarctic terrains, providing a theoretical foundation for different applications, such as lake ice surface bathymetry inversion