Analysis of Shoreline Change Based on Littoral Cell along the East Coast of the Korean Peninsula Using Satellite Imagery

This study aims to quantitatively analyze shoreline change along the east coast of the Korean Peninsula, including the data-limited region, using satellite-based remote sensing techniques, and to examine the spatial structure of littoral cells. Sentinel-2 satellite imagery from 2015 to 2025 was used to extract shorelines, and outliers were removed using a density-based clustering algorithm (DBSCAN). Validation against field survey data showed a root mean square error (RMSE) of 16.21 m and a coefficient of determination (R2) of 0.815. Based on the constructed long-term shoreline dataset, beach width variations were calculated and tidal corrections were applied. Dimensionless indicators representing shoreline orientation, beach-width asymmetry, and embayment were defined, and geographic coordinates were additionally included as spatial constraints. Dimensionality reduction and hierarchical clustering were then used to classify spatially adjacent coastal segments with similar sediment-transport characteristics. The results indicate that the east coast of the Korean Peninsula can be classified into four major sediment transport systems, with some sections showing sediment transport extending across the inter-Korean boundary. Furthermore, spatial heterogeneity was observed at the local scale, where erosion and accretion coexist.