BATHYMETRIC METHOD OF NEARSHORE BASED ON ICESAT-2/ATLAS DATA-A CASE STUDY OF THE ISLANDS AND REEFS IN THE SOUTH CHINA SEA

Photon-counting Light Detection and Ranging (LiDAR) can penetrate a certain depth of water and provide reliable date support for water depth information extraction. Taking the islands and reefs in the South China Sea as an example, this paper uses the only in-orbit spaceborne photoncounting LiDAR - Ice, Cloud and land Elevation Satellite2/Advanced Topographic Laser Altimeter System (ICESat-2/ATLAS) to carry out research on depth extraction and accuracy evaluation in shallow water areas of islands and reefs. Aiming at difference in the density distribution of water surface and bottom photons, this study respectively utilizes the interval estimate and the modified Ordering Points to Identify the Clustering Structure (OPTICS) to filter out noise photons, and the modified OPTICS is changed twice by filter parameters. Then, bathymetric extraction is realized by refraction correction and tide correction. Finally, the manual labeling photons and airborne bathymetric LiDAR data of South China Sea is used to evaluate the denoising and bathymetric accuracy.