Study on seasonal variety of ocean color and delimitation between river and sea in Yellow River Estuary based on TM images

摘要

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 0.71 μg/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 bandl, 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.