The airborne LiDAR bathymetry (ALB) is one of the most effective technologies to retrieve the topographic and bathymetric maps of coastal zones. The water depth is typically calculated from the sea surface and seafloor peak positions of the ALB waveforms. However, the seafloor topography slope within the footprint scale causes the seafloor waveform stretching and peak shifting when the blue-green laser beam reaches the seafloor, which induces the timing uncertainly to influence the accuracy of the measured seafloor topography. In this work, a correction method in the airborne LiDAR bathymetric error caused by the effect of seafloor topography slope at the footprint scale is proposed to reduce the influence.In this method, the ALB seafloor waveform simulation model is achieved based on the footprint-scale topography parameters model, taking into account the effect of seafloor topography. The ALB error correction equation is obtained based on the quantitative relationship between seafloor topography slope and peak timing of echo waveforms. The developed method is used to correct the ALB data collected near Ganquan Island in the South China Sea and verified by the topography data captured by a ship-borne multi-beam echo sounder.Results show that the mean absolute error and root mean square error are reduced to 9.4 and 12.3 cm after the correction, respectively. Specifically, MAE and RMSE decreased by 35.6% and 33.5%, respectively.

remote sensing;airborne LiDAR bathymetry (ALB);seafloor topography;seafloor slope;depth correction;laser beam footprint at the seafloor