最近50年来莱州湾西-南部淤泥质海岸地貌演变研究

Study on the geomorphic evolution of the muddy coast along the southern-western Laizhou Bay over the past 50 years

在野外考察和前人研究基础上,以1976-2009年间4个时相的MSS/ETM+遥感影像和1958、1984、2002年测量的三期海图为主要数据源,运用3S(RS/GIS/GPS)技术,对最近50年来莱州湾西-南部淤泥质海岸地貌演变进行了研究。结果表明:近50年来,以青坨子为界,莱州湾西、南岸虽均为淤泥质海岸,但其海岸地貌演变存在明显的差异性。具体表现在,莱州湾西岸与南岸的海岸线和等深线变迁时间不同步、变迁幅度差距大、岸线形态不同;莱州湾西岸和南岸地貌类型空间分布不同,转换的趋势、净方向、速率和幅度差异也十分明显以及莱州湾西岸和南岸水下地貌冲淤变化差距悬殊等。莱州湾西海岸的地貌演变与黄河河口-三角洲的地貌变迁基本正相关,变化幅度也较大,后期受到人类活动影响较为明显。海湾南岸的地貌演变受人类活动的影响也日益显著,但其海岸地貌的演变与西岸黄河口-三角洲地貌的剧烈变迁基本无关,莱州湾西岸黄河入海水沙的减少乃至断流对南岸冲於状态变迁也未有显著影响。

Taking the 4-phase MSS/ETM＋ remote sensing images from 1976 to 2009 and sea charts surveyed in 1958, 1984 and 2002 respectively as main data sources, the dynamical geomorphic evolution of the muddy coast along the southern-western Laizhou Bay in the past 50 years has been studied by using 3S （RS/GIS/GPS）. According to the results, taking the Qingtuozi as the boundary, the geomorphic evolution of the western and southern coasts along the hay shows distinctively different over the past 50 years, though both parts are made up of the muddy sediments. Details are shown as follows： the evolution of the coastline and isobaths between the two parts are not synchronized, and amplitude of the changes presents greatly different, as well as the disparate patterns. There remains great difference in the spatial distributions of the coastal geomorphic types between the two parts, and its transferred rate, net-direction and amplitude are obvious discrepant. Erosion of the offshore slopes between of the two parts has great gap too. Coastal geomorphologicsal of the western Laizhou Bay which has a positive correlation with the evolution of Yellow River estuary-delta, makes a drastically changes, and suffers an obvious influence from the human activities in the late period. The geomorphic evolution of the southern coast is affected by human activities either, but it almost has nothing to do with the severe evolution in the Yellow River delta of the western bay. The decrease and even the cutoff of the water and sediment discharge from Yellow River into the sea in the western bay have no significant effects on the erosion-deposition of the southern coast too.