297 / 2024-02-29 09:50:23

SBAS-inSAR-based study on the evolution of marshland scouring and siltation in Poyang Lake Wetland Reserve.

poyang lake; SBAS-insar;siltation;soil erosion

Poyang Lake is the largest freshwater lake in China, and its huge difference between high and low water levels during the year has nurtured a unique wetland ecosystem. In recent decades, the sediment load of the Yangtze River downstream of the Three Gorges Dam has decreased dramatically, and at the same time, with the construction of water conservancy facilities in the upstream of the inlet river and afforestation activities, the sand content of the inlet river has changed significantly, and the original flushing and siltation patterns have been altered, which has had a great impact on the wetland ecosystem succession, and it has become a high priority for the protection of the wetland to accurately master the situation of the wetland siltation and scouring. In this study, the small baseline subset interferometric synthetic aperture radar (SBAS-InSAR) method was adopted to analyze the wetland scouring and siltation situation in Poyang Lake Reserve by using 21 Sentinel-1A satellite datasets during the dry period of October 2022 to January 2024, and verifying the accuracy of remote sensing inversion by combining with the observation data of scouring and siltation in typical floodplain wetlands. The results show that the SBAS-inSAR inversion results are in good agreement with the measured results, which can be used for the subsequent study of wetland scouring and siltation in the field. The spatial distribution of wetland scouring mostly occurs along the outer edge of the large disc-shaped lake, and the distribution of scouring and siltation areas in the middle of the lake area has a strip-like variability. This study provides data support for the evolution of wetland microtopography in Poyang Lake and the macro-control of lake water and sand.