Continuous Expansions of Yangtze River Islands After the Three Gorges Dam Tracked by Landsat Data Based on Google Earth Engine

IEEE Access

Nan Xu¹  Jinyan Sun²  Lei Ding³  Zuoji Huang⁴  Yue Ma⁵  Zhengjia Liu⁶ 

[1] Huaihe River Institute of Hydraulic Research, Hefei, China;Anhui Key Laboratory of Water Conservancy and Water Resources, Anhui &x0026;College of Marine Science and Engineering, Nanjing Normal University, Nanjing, China;Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China;Key Laboratory of Port, Waterway, and Sedimentation Engineering, Ministry of Transport, Nanjing Hydraulic Research Institute, Nanjing, China;School of Electronic Information, Wuhan University, Wuhan, China;

关键词: Google Earth engine;    river islands;    remote sensing;    the Yangtze river;    the three Gorges dam;   

DOI  :  10.1109/ACCESS.2020.2994628

来源: DOAJ

【 摘 要 】

Understanding the change of river islands is essential for water conservancy construction, channel navigation safety, and industrial/agricultural production. Yangtze River is the largest river in China; however, there are few long-term monitoring results on the changes of Yangtze River islands. To fill this gap, Landsat data available on the Google Earth Engine (GEE) were used to obtain the annual changes of the Yangtze River islands located from the lower reaches of the Three Gorges Dam (TGD) to the Yangtze River delta during 1986-2017. Moreover, we focused on the changes of those islands before and after the construction of the TGD. Annual areas of all river islands were calculated and spatial-temporal pattern of Yangtze River islands were analyzed. Our satellite observation results show continuous expansions of Yangtze River islands after the construction of the TGD in 2003. For the total 138 river islands, in three stages: before 2003, after 2003 and in the 32-year study period, 68, 118, and 124 river islands showed increasing trends, with the net increase of 286.47 km², 417.49 km², and 665.62 km². For the total 92 river island groups (138 islands), percentages of river island expansion are 41.30% (before 2003), 80.43% (after 2003) and 88.04% (1986-2017). Moreover, we found 10 newly developed river islands, with a net expansion of 87.42 km² and an expansion rate of 2.73 km²/year. The significant decrease (2-4 m) in water level before and after the TGD might be the main factor that results in the observed expansion of Yangtze islands downstream the TGD. We also highlighted the importance of using all available Landsat imagery for tracking the changes of river islands. Our satellite-derived dataset provide reference data for the land use planning and environmental protection in the Yangtze River drainage basin.

【 授权许可】

Unknown