Optimization of a multi-sensor satellite-based waterline method for rapid and extensive tidal flat topography mapping

Tidal flats are crucial ecosystems at the land-ocean interface. As the ecological value of tidal flats is emphasized, there is a need for precise tidal flat topographic maps as basic data for ecosystem protection and restoration planning. This study presents an optimized satellite-based waterline method for mapping the topographic changes in tidal flats, along the west coast of South Korea. We evaluated the accuracy and efficiency of digital elevation model (DEM) generated using multi-sensor satellite data (Landsat 8/9, Sentinel-2A/B, and Sentinel-1A) collected over a one-year period. The optimal data collection period was found to be 5 months, as extending the collection period beyond this did not result in a significant improvement in DEM quality, based on the mean absolute error (MAE) threshold. At a data collection period of 5 months, the Fusion DEM had an MAE of 25.6 cm, making it approximately 8.16% more accurate than the Optical DEM and about 49.56% more accurate than the SAR DEM. Our method accounts for rapid environmental changes due to climatic effects and human activities, providing a reliable model for monitoring vital tidal-flat ecosystems. • Tidal flats are crucial ecosystems at the land-ocean interface • Enhanced the method for mapping tidal flat topography changes on South Korea's west coast • Evaluated the use of multi-sensor satellite data to create tidal flat digital elevation model (DEM) • Integrating optical and SAR data improved DEM accuracy and shortened data collection time. • This study provides a guideline for monitoring methods considering the rapidly changing tidal flat environment.