Spatiotemporal lake area changes influenced by climate change over 40 years in the Korean Peninsula

Water resources in lakes of the Korean Peninsula play a significant role in society and ecosystems in both South and North Korea. This study characterized spatiotemporal changes in the lake area during the dry season (March-May) in the Korean Peninsula over the last 40 years. The satellite images (Landsat 5-9) were used to derive annual areas of 975 lakes during the dry season from 1984 to 2023. Our analysis indicated that the MNDWI is the optimal remote sensing-based index for delineating lake areas in the Korean Peninsula, with an overall accuracy of 92.3%. Based on the selected index, the total lake areas of the dry seasons have increased from 1070.7 km² in 1984 to 1659.3 km² in 2023, mainly due to newly constructed dam reservoirs. While the detailed changes in lake area vary, we found divergent results based on their sizes. The large lakes (> 10 km²) showed their area increased by 0.0473 km² (0.1%) every year and have more influences from climate change. On the contrary, the small lakes (≤ 10 km²) have area decreases by 0.0006-0.006 km² (0.15-0.5%) every year and have less influence from climate change. This study shows that the spatiotemporal lake area changes are determined by either climate change or human activity.