Long-Term Remote Sensing Dataset of Water Color in Chaohu Lake, 2000–2024

Water color is an integrated representation of the optical properties of water bodies and can comprehensively reflect the absorption and scattering characteristics of water constituents, such as chlorophyll-a (Chl-a), suspended matter, and colored dissolved organic matter (CDOM), providing an effective approach for the consistent characterization and long-term monitoring of water quality status. Large shallow lakes are characterized by shallow water depths, short water exchange cycles, and a high susceptibility of bottom sediments to resuspension, making them highly sensitive to watershed environmental changes and anthropogenic disturbances.

Chaohu Lake is one of the five major freshwater lakes in China and a typical large shallow lake in the middle and lower reaches of the Yangtze River. Based on the MODIS MOD09A1 surface reflectance product, a long-term water color dataset for Chaohu Lake from 2000 to 2024 was developed using an independently developed high-accuracy water color retrieval model. Water color was characterized by the Hue Angle (α), and annual mean values were calculated from the within-year remote sensing retrieval results for each year, with a spatial resolution of 500 m.