Temporal and spatial evolution research of Dongting Lake based on Landsat-8 remote sensing images

Dongting Lake, located in Hunan Province, China, is the second-largest freshwater lake in the country and a crucial ecosystem and biodiversity hotspot. Investigating the temporal and spatial evolution of Dongting Lake's water areas is conducive to regional water resource development and provides assurance for regional ecological balance. In this study, Landsat-8 OLI remote sensing images from the years 2017 to 2021 were utilized. The normalized difference water index (NDWI) water threshold value method was employed to extract the water area of Dongting Lake. The study analyzed the temporal and spatial evolution of Dongting Lake, delving into the migration direction of the Dongting Lake basin's centroids, providing a reference basis for the sustainable development of Dongting Lake. The results indicated that the water area of Dongting Lake decreased from 913.65 km² in 2017 to 723.14 km² in 2019, followed by an increase to 866.65 km² in 2021. The centroids of Dongting Lake shifted southwestward from 2017 to 2019 and then east-southeastward from 2019 to 2021.