Dynamic monitoring and spatiotemporal change analysis of Chaohu Lake algal bloom based on Sentinel-2 remote sensing data

To study the patterns of algal blooms in Chaohu Lake, this article uses Sentinel-2 images as the data source and extracts algal bloom using the Normalized Difference Vegetation Index (NDVI). From 2019 to 2022, the dynamic monitoring of algal bloom in Chaohu Lake is conducted, analyzing the temporal and spatial changes in algal blooms, exploring the driving factors of algal blooms in Chaohu Lake. The results indicate that: (1) From 2019 to 2022, the scale of the annual outbreak of algal bloom in Chaohu Lake gradually decreased. The degree of water blooms significantly decreased. (2)Chaohu Lake has strong seasonal changes in water blooms, with severe outbreaks in summer and autumn when temperatures are higher, indicating that temperature is the main factor driving the outbreak of water blooms. (3) As the main pollutant discharge area of Hefei urban area, the northwest of Chaohu Lake is the core area for algal blooms, indicating that water quality is an important influencing factor leading to algal blooms in Chaohu Lake; From the spatial changes in the movement of algal blooms from the northwest and the coast of east lake towards the middle of the lake, and from the middle of the lake to the northwest, it is found that wind speed is more likely to suppress the outbreak of algal blooms.