Evolution And Genetic Analysis Of Yangtze River Estuary Shoreline Based On 3S Technology

The coastal beaches of the Yangtze river estuary is the sensitive interactional area of the land and oceans,and is also the important and valuable land resources in Yangtze river delta area. Under the natural phenomena and human factors, the evolution of The Yangtze river estuarine shoreline is complex, and the beach erosion and deposition are more complex. So It has great significance in the sustainable development of the Yangtze River Delta region to study the law and analysis the causes of the Yangtze River estuarine shoreline evolution.In this paper, the analyses are mainly based on GIS、RS、GPS and DSAS technology and using Landsat MSS、TM、ETM+、OLI and HJ-1A CCD1、GF-1 WFV multi period remote sensing image of 1974, 1985, 1995, 2006 and 2015.Firstly, the position of Yangtze River estuarine shoreline and the distribution of suspended sediment are extracted. Secondly, the uncertainty of extracted shoreline position is analyzed. Finally, the temporal and spatial variation of the Yangtze River estuarine shoreline in the past 40 years is studied and its causes are analyzed. The main research results are as follows:1.In the remote sensing images, the different shoreline types have different characteristics in color, texture and spatial correlation.According to these different characteristics, we have established the coastline interpretation signs of bedrock shoreline, sandy shoreline, the muddy coast, estuary shoreline and artificial shoreline. By using different methods, the shoreline of the Yangtze River estuary is successfully extracted.2.Combined with GIS spatial analysis tools and DSAS technology, the length of shoreline, the changing area of the scouring and silting, the rate of shoreline moving and the distribution of different types of shoreline are studied, and the change of shoreline of the typical section are analyzed in detail. The analysis results show that the whole study area is in a state of deposition. The shorelines in the north and east coasts of the Chongming Island, the north of Changxing Island and the eastern coastal of Hengsha Island change obviously. The artificial shoreline of the Yangtze River estuary has a growing trend in the proportion.3.In this paper,we also compared the result of suspended sediment concentration inversion based on HJ-1A CCD1、GF-1 WFV and Landsat8 OLI sensor data, high spatial resolution of GF-1 WFV and the high temporal resolution of HJ-1A CCD1 have greater advantages, which further confirmed the value of domestic satellite data applications.4. Based on the analysis of the shoreline change and the distribution of suspended sediment concentration, combined with geological data and related statistical data, the reasons for the change of the Yangtze River shoreline are analyzed from two aspects of natural factors and human factors. The results show that the change of the Yangtze River shoreline is the result of the interaction of natural factors and human activities. And human activities occupy the dominant position, just as sea farming, agricultural reclamation, port and dock construction, urban construction and so on; Natural factors are also the important reason for the Yangtze River shoreline changes, mainly including sediment supply change and climate change.