Study On Alluvion And Erosion Of Modern Yellow River Delta With Remote Sensing Data

In order to ensure a sustainable development of Yellow River delta, the research on its coast line evolution is a hot issue now. Based on 2m contour of surveyed bathymetry from 1976 to 1999 and mean-high-tidal line distracted from remote sensing images acquired by Landsat-5 TM from 1976 to 2000 respectively, quantitative analysis about alluvion and erosion as well as the relationship between accretion of modern Yellow River delta and the water and sediment discharge of Yellow River is made, and the results indicate the mean-high-tidal level is more effective than 2m contour of the bathymetry. It is found that the accretion of Modem Yellow River delta is becoming less and less, what's more, erosion is even more than alluvion in some recent years. Diaokou promontory has been eroded seriously since Yellow River changed its course in1976. Qingshuigou promontory has accumulated a lot because it is the temporary running course of Yellow River. Coast line between Diaokou promontory and Wanwangou and coast line between Qingshuigou promontory and Zhimaigou are relatively stable. A statistical model is developed and indicates high correlation between the accretion of modem Yellow River delta and the water and sediment discharge of Yellow River, and the model shows the necessary water and sediment discharge per year to ensure the equilibrium of alluvion and erosion of Yellow River delta. Some factors affecting the alluvion and erosion of the Yellow River delta are given and analyzed, including human activities, global warming and sea level rise, deep structure, deposits in the delta, local climate, some ocean factors such as current, wave, tide.Multispectral data for bathymetry is often performed in relatively clear shallow waters, up to now, no one use multispectral data for bathymetry in estuary waters of Yellow River, where the highest sediment concentration in the world has been observed. In another part of this thesis, Multispectral data acquired by landsat-5 TM and in situ data are used for bathymetry in estuarine waters of Yellow River. Statistical models based on one band and two bands of TM respectively are developed. The results indicate that within the range of visible light, with the increase of sediment concentration, water radiance becomes stronger towards longer wave light. With the model of Z=Aln (TM2/TM4) +B, retrieved water depths of the study waters are accurate to a RMS error of 1.4m and 1.3m in and out the shear front of the Yellow River mouth for 0-10m water depth, 0.8m for water depth of 10-16m, where the highest sediment concentration has been observed. In another field about 15 kilometers away in the north of Yellow Rivermouth, with the model of Z=ATM3+B, retrieved water depths are accurate to a RMS error of 1.5m. So, multispectral data for bathymetry in estuarine waters of Yellow River is feasible, and it can be auxiliary to traditional bathymetry.