SATELLITE-BASED SHORELINE OBSERVATION OF EASTERN CHONGMING ISLAND, CHINA, 1974-2013

摘要

Dongtan, located at the east of Chongming Island in Yangtze Estuary, experiences continuous progradation, due to the deposition of sediment from the Yangtze River. Multi-temporal remote sensing data of Landsat and HJ 1B spanning from 1974 to 2013 were used to examine the dynamics of Dongtan. Results show that the land area of Dongtan increased by 185.28 km2, with average shoreline progradation of 4.2 km. The period of 1989-2002 had the fastest progradation, with a net progradation area of 85.98 km~2. These shoreline dynamics were closely related to sediment load delivered by the Yangtze River and artificial sea reclamation. Rapid progradation during 1989-2002 was mainly ascribed to the sea reclamation works performed in 1990s, including Tuanjiesha reclamation, Dongwangsha reclamation and 98-bank reclamation, with reclamation areas of 18.27, 44 and 22.67 km~2 respectively. Encryption observations reveal that shoreline progradation, however, had slowed since 2002 due to the entrapment of Three Gorges Reservoir (TGR). When project to the future, minor progradation or retreat can be expected in response to the decline of Yangtze sediment supply.