Multi-Temporal Analysis of Shoreline Change at Lara Beach (Antalya, Türkiye) from 1984 to 2025 Using Google Earth Engine and DSAS
Abstract
This study examines shoreline change at Lara Beach, located on the Antalya coast of Türkiye, over the 1984–2025 period using a Google Earth Engine (GEE)-based remote sensing workflow and comparison with the Digital Shoreline Analysis System (DSAS). The main aim is to identify the direction, magnitude, and alongshore spatial variability of long-term shoreline change. The analysis was carried out using Landsat Collection 2 Level 2 Surface Reflectance imagery for seven primary epochs representing 1984, 1990, 2000, 2010, 2015, 2020, and 2025. Shorelines were extracted in the GEE environment from median composites using the Modified Normalized Difference Water Index (MNDWI), and shoreline change was assessed along 84 transects spaced at 100 m intervals using Net Shoreline Movement (NSM), End Point Rate (EPR), and Linear Regression Rate (LRR).
The results show that Lara Beach exhibits a weakly negative long-term average change, but this pattern does not correspond to uniform shoreline retreat along the entire coast. In the GEE-based analysis, mean NSM, mean EPR, and mean LRR were calculated as -0.69 m, -0.02 m/yr, and -0.03 m/yr, respectively. Of the 84 valid transects, 41 were classified as erosional and 43 as accretional. This distribution indicates that erosional and accretional sectors coexist along the same shoreline, despite the slightly negative overall mean. Period-specific results further show that the shoreline advanced seaward in 1990, retreat became more pronounced during 1990–2000 and 2000–2015, and partial recovery occurred in some sectors after 2015. Comparison between GEE and DSAS yielded correlation coefficients of 0.838 for NSM, 0.779 for EPR, and 0.733 for LRR. Overall, the findings indicate that Lara Beach is not a uniformly erosional coastline, but a spatially heterogeneous coastal system in which erosional and accretional sectors coexist along the same reach.
Keywords
Lara Beach, shoreline change, Google Earth Engine, DSAS, remote sensing
Supporting Institution
This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
Ethical Statement
Ethics committee approval was not required for this study because it is based on publicly available satellite imagery, remote sensing/GIS analyses, and non-invasive field observations, and does not involve human participants, animals, personal data, or experimental procedures.
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