Modeling the effects of surface and bottom geometries on LiDAR bathymetric waveforms

LiDAR bathymetric biases due to geometric changes at the air-water and water-bottom interfaces are investigated based on calculations made with a modified version of the waveform simulator Wa-LID. Main assumptions include a homogeneous water column and a spaceborne LiDAR having a footprint smaller than 50 m and a wavelength centered at 532 nm. Preliminary results showed major temporal modifications on second Lidar return (up to 100 cm or 10 ns) due to tilted bottoms. This shift was in average >6-fold the maximum bottom depth bias originated from capillary waves forming at the air-water surface.