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 km in 1984 to 1659.3 km 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 km) showed their area increased by 0.0473 km (0.1%) every year and have more influences from climate change. On the contrary, the small lakes (≤ 10 km) have area decreases by 0.0006-0.006 km (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.