Using Landsat-5 TM image on November 24, 2004 and May 13, 2005; and quasi-synchronous surveyed data, the dynamic change of suspended silt and chlorophyll a in the Yellow River Estuary were inversed and the coastal line of this region was interpreted. The mean correlation coefficient between measured data and spectral signature value of every image is 0.85 which proved that the inversion is satisfying. The results show that there were different seasonal patterns between suspended silt and chlorophyll a. The concentration of suspended silt in the surface seawater in the estuary averaged 307.8mg/L in winter and 352.7mg/L in spring. While the Chlorophyll a concentration in the surface seawater averaged 0.71μg/L in winter and 0.59μg/L in spring. The surveyed data show one distinct boundary in concentration of suspended silt along the sampled stations. The reversed data from band1, band2, band3, band4 and band6 also show the same boundary at the same location.
The results of interpreting coastal line show that there is a rapid alteration in the Yellow River Estuary coastal line. Although in low or median water level period, with advance extent of the coastal line, there were prominent on the south shore beside the Laizhou Bay than the other places. Integrated with the practical measured data, by means of RS method, the study can get the same conclusion as the other methods did on judging boundary sign between River and Sea. So it also can be regarded as an efficient method to confirm boundary of River and Sea, and be the most available way to study dynamic state of coastal line of river mouth.
This study aims at discovering changes of ecosystem service value based on spatial-temporal variety of land use features on the coastal area in Lianyungang City from 1978 to 2000. Three LANDSAT images (1978 MSS, 1987 TM and 2000 ETM) were used to estimate changes in the size of six land-use categories (forest, cropland, urban, wetland, lakes/rivers and coastal water). Coefficients which integrated from Costanza et al.'s (1997) ecosystem services valuation model and Xie Gaodi et al.'s (2003) "ecosystem services value unit area of Chinese terrestrial ecosystems" were used to estimate changes in ecosystem services delivered by each land categories, and a sensitivity analysis was conducted to determine the affecting factors of ecosystem service value. The total annual ecosystem service values in coastal area of Lianyungang City decreased from RMB 8.23×10^9 in 1978 to RMB 7.53×10^9 in 1987, however it increased from RMB 7.53×10^9 in 1987 to RMB 10.73×10^9 in 2000. The decline of ecosystem service value from 1978 to 1987 is largely attributable to 53.49% loss of forest at the same period, while the increase of service value is contributed by 147.70% increase of wetland from 1987 to 2000. Change of wetland and forest has the major contribution to the change of total ecosystem service value of Liangyungang city. Waste treatment, water supply and climate regulation are the dominant ecosystem services of this area. Forest and wetland should be strictly conserved in further urban development.
Evaluating status and possibility of desertification is an important field in arid and semi-arid zone. For Gansu province is located in inner northwestern China, fragile environment and irrational human activity have made it a relatively serious area of desertification in northern China, and a main source of dust storm happening in China every year as well as. The paper acquires data of variety of land use and desertification on Gansu province from 1986 to 2000, by interpreting TM images of the two periods with GIS software ARC/INFO. Then, on the basis of the data, the study uses index of desertification extent to analyze spatial pattern of desertification on the province. The result indicates that on desertification scale, the Hexi corridor exceeds the other areas, in contrast to it that desertification extent of the Hexi corridor is less than it of the other areas. Based on the above results, with support of integration of ARC/INFO, statistic software SPSS and office software EXCEL, the study uses means of principal component analysis (PCA) to evaluate potential extent of every county on possibility of desertification. The result shows that the possibility of desertification of the Hexi corridor and the Gannan region exceed it of other areas, which is in accord with present spatial pattern of desertification scale on Gansu province.