现代黄河三角洲海岸线变迁及滩涂演化

SHIFTING OF COASTLINE AND EVOLUTION OF TIDAL FLAT IN MODERN YELLOW RIVER DELTA

通过对遥感影像数据和实测水深数据的研究,采用遥感(RS)和地理信息系统(GIS)技术,分析了现代黄河三角洲河口区滨海湿地面积的变化规律。结果表明,黄河1976年改道清水沟流路以来,三角洲海岸线总的变化趋势是现行河口海岸线明显向海淤进,而北部废弃河口岸线则明显侵蚀后退,南部莱州湾地区冲淤幅度不太明显,岸线变化不大。1976年黄河改道清水沟流路初期,滩涂面积快速增长,1976—1987年滩涂面积呈环状分布;随着滩涂围垦以及油田建设等人类活动的进行,同时清水沟流路发育成熟,河口造陆速率减缓,导致1981—1987年这一时段滩涂面积略有减少;1996年清八出汊,黄河再次改道,新河口迅速淤积,故河口沙嘴冲刷的沉积物南移,使得1998年滩涂面积稍有增长;此后新河口淤积的同时老河口侵蚀,再加上人为活动的不断影响,滩涂面积又呈减少之势。

Based on TM images and depth data accumulated in the past years, using such technology as GIS and RS, we studied the changes of Coastal Wetland in the Yellow River delta. It was revealed that the coastline was progressed in the estuary, retreated in the north coast by erosion of the abandoned delta, and remained stable in the south of the Laizhou Bay since the River took the course of the Qingshuigou channel to the sea in 1976. In the early stage after the shifting of main channel, the tidal flat grew rapidly. And during the period of 1976--1987, the tidal flat was expanded in a circle like around the river mouth. The area of tidal flat was slightly reduced during 1981--1987 due to agricultural cultivation and oil development. The Yellow River changed its course again in 1996. The new river mouth was rapidly silting up, the area of tidal flat grew slightly near the river mouth in 1998, whereas the old river mouth was under intensified erosion. As the result, the tidal flat of the Yellow River has been in an overalt status of reducing since then.