Study on Poyang Lake Hydrologic Regime Using Sentinel-1/3 Data

Poyang Lake is the largest freshwater lake in China and affected by floods from the Yangtze River basin every year, where the fluctuation of water level affects the ecological environment of Poyang Lake. The Sentinel satellites, provide persistent data for lake water area and level monitoring. Sentinel-1 overpasses Poyang Lake more than 2 times a month. With its high temporal-spatial resolution, the Sentinel-1 SAR data can be used to retrieve the water area accurately. Sentinel-3, equipped with SRAL altimeter, can be used to monitoring lake water level in high tempral/spatial resolution. After pre-processing, the Sentinel-1 SAR data were used to map the water surface using U-Net convolutional network. The Sentinel-3 altimeter data were processed to retrieve the day water level for Poyang Lake. Meanwhile, we collected the water level data from hydrologic information wetsite. Finally, we compared these 3 kind of hydrologic data and found that 1) the U-Net water body mapping method can extract water body in high accuracy, 2) our water level retrieval algorithm can retrieve water level, 3) compared to the water level data, there exists a high correlation between the water area and water level.