[A-CG37] Satellite Earth Environment Observation

[ACG37-P19] Topographic mapping of Taiwan's coastal area using optical satellite images

*WenSin Wu¹, Kuo-Hsin Tseng¹ (1.National Central University, Taiwan)

Keywords:coastal, intertidal zone, DEM, tide, optical satellite, DTU16

Taiwan has a coastline of about 1,200 km and the intertidal zone plays an important role in ecological and environmental perspectives. The topography of the intertidal zone changes rapidly due to current erosion, accumulation, and human exploration. For the monitoring of topographic changes in the intertidal zone of Taiwan, airborne LiDAR was used in the past, which was time-consuming, labor-intensive, and expensive. Therefore, this study aims to use cost-free optical satellite images to reconstruct a Digital Elevation Model (DEM) with acceptable accuracy. By using the Modified Normalized Difference Water Index (MNDWI) and DTU16 global ocean tide model, the water body and land area are classified and the map of inundation probability is leveled. However, the optical images captured by the sun-synchronous satellites take images at the same local time, and the tide of Taiwan mostly exhibits as semidiurnal, which would cause the optical images to have a higher probability during higher tides and lower tides. In this research, the distortion of the DEM caused by the uneven sampling is reduced by the simulated model and the standard deviation of intertidal DEM is better than 0.5 m.