Refraction correction and coordinate displacement compensation in nearshore bathymetry using ICESat-2 lidar data and remote-sensing images

In nearshore bathymetry based on the Ice, Cloud, and Land Elevation Satellite-2 (ICESat-2), water refraction causes a position displacement of the seafloor signal photon, decreasing the bathymetric accuracy. A novel refraction-correction method is proposed for the ICESat-2. Based on the experimental results and statistical analysis, it is illustrated that the displacement in elevation direction reaches several meters at the relative depth. The displacement in the along- and cross-track directions is very small, ranging from millimeters to centimeters. Finally, the relationship of refraction displacements with various incident angles and water depths is analyzed in detail, revealing the nearshore bathymetry characteristics of ICESat-2.