Water level detection in coastal areas with spaceborne LiDAR: accuracy assessment of GEDI and ICESat-2 data

This study evaluates the accuracy of spaceborne LiDAR data from the Global Ecosystem Dynamics Investigation instrument (GEDI) and the Ice, Cloud and Land Elevation satellite (ICESat-2) for measuring water surface elevation across ten coastal bays on the Atlantic coast of the United States of America. Our results show that the ICESat-2 measurements are more accurate than GEDI measurements with a root mean squared error of 0.08 m and 0.42 m, respectively. However, GEDI provides denser spatial and temporal coverage. Evaluation of instrumental and environmental factors affecting the accuracy of the GEDI water surface elevation resulted in no significant relation between the elevation error and solar elevation, beam type and wind speed conditions. Our study showcases the capabilities of spaceborne LiDAR data for augmenting the spatial coverage of available in-situ water level gauges.