王世雄,范勇勇,刘猛,等. 黄河清水沟废弃河口冲淤时空变化特征[J]. 海洋地质前沿,2022,38(5):1-11. DOI: 10.16028/j.1009-2722.2021.082
    引用本文: 王世雄,范勇勇,刘猛,等. 黄河清水沟废弃河口冲淤时空变化特征[J]. 海洋地质前沿,2022,38(5):1-11. DOI: 10.16028/j.1009-2722.2021.082
    WANG Shixiong, FAN Yongyong, LIU Meng, et al. Temporal and spatial variations of erosion and accumulation off the Qingshuigou mouth of the Yellow River[J]. Marine Geology Frontiers, 2022, 38(5): 1-11. DOI: 10.16028/j.1009-2722.2021.082
    Citation: WANG Shixiong, FAN Yongyong, LIU Meng, et al. Temporal and spatial variations of erosion and accumulation off the Qingshuigou mouth of the Yellow River[J]. Marine Geology Frontiers, 2022, 38(5): 1-11. DOI: 10.16028/j.1009-2722.2021.082

    黄河清水沟废弃河口冲淤时空变化特征

    Temporal and spatial variations of erosion and accumulation off the Qingshuigou mouth of the Yellow River

    • 摘要: 黄河于1996年人工改汊至清8入海是导致清水沟废弃河口岸线蚀退和海底侵蚀冲刷的主要诱因。但目前有关清水沟废弃河口海底冲淤演化对黄河人工改道的响应的认识尚有不足。因此,利用现代黄河三角洲毗邻海域多年的水深资料和Landsat卫星遥感影像,综合分析了清水沟(废弃)河口在1996—2015年的岸线变化及冲淤时空变化。结果表明:黄河清水沟废弃河口沙嘴两侧蚀退速率的变化存在明显的时空差异性。黄河改道初期(1996—2002年),研究区海底冲刷速率较快,年均冲刷速率约为0.03~0.05 km3/a;2002—2007年,研究区海底冲刷速率大幅降低至约0.02 km3/a;2007—2010年,随着黄河口位置再次向北迁移,研究区海底年均冲刷速率增大至约0.026 km3/a;2010—2015年,研究区海底年均冲刷速率减缓至约0.01 km3/a,远小于1996—2002年黄河改道初期时的水平。同时,基于Delft3D模式构建了黄河三角洲高分辨率三维水动力模型,定量研究了清水沟废弃河口潮流与冬季波浪变化对海底冲淤变化的影响,结果表明波浪和潮流在河口侵蚀过程中扮演着不同的角色。一方面,潮流与波浪在三角洲前缘斜坡处形成的高底剪切应力区是使得该区域形成侵蚀中心的主要原因。清水沟废弃河口岸线不断向陆方向蚀退以及侵蚀冲刷所造成的研究区整体水深增加使得潮流与波浪对海底的侵蚀冲刷作用逐渐减弱,最终使得近年来研究区海底冲刷速率不断减缓。另外,波浪在河口近岸区形成的高底剪切应力是造成河嘴两侧叶瓣差异侵蚀和近岸区形成侵蚀中心的主要动力机制。同时,潮流、波浪与海底冲淤变化间的相互作用对于该区域冲淤演化模式有着重要影响。

       

      Abstract: The deltaic river course of the Yellow River was diverted artificially northward at the Qing8 of the Qingshuigou channel to the current channel. The channel shift resulted in a decrease or cutoff in the sediment supply from the river. However, the response of the tempo-spatial variation in erosion and accumulation off the abandoned Qingshuigou mouth to the channel shift has not been well studied. Based on multi-years bathymetric data and Landsat satellite remote sensing images off the Yellow River Delta, the tempo-spatial variations of erosion-accumulation off the abandoned Qingshuigou mouth were analyzed comprehensively. In the early stage of the Yellow River diversion (1996—2002), the seafloor erosion rate in the study area was relatively fast, and the average annual seafloor erosion rate was about 0.03-0.05 km3/a. From 2002 to 2007, the value was significantly reduced to about 0.02 km3/a. During 2007—2010, as the Yellow River mouth diverted northward again in 2007, the average annual seafloor erosion increased to about 0.26 km3/a. In the years of 2010—2015, the value reduced to about 0.01 km3/a again, which was much lower than the level at the initial stage of the Yellow River artificial diversion in 1996. Meanwhile, the tidal regime changes and its response to tempo-spatial variation of erosion-accumulation off the abandoned Qingshuigou mouth were simulated using the Delft-3D model. The results indicated that waves and currents played significant but different roles in the erosion and accumulation of seabed in the study area. On one hand, The high bed shear stress area formed by the tidal current and wave on the slope of the delta front caused the area to be severely eroded after the Yellow River rerouted. In addition, as the abandoned Qingshuigou mouth gradually eroded landward and water depth at the slope continuously increased, the influence of tidal current and wave to seafloor decreased gradually. Finally, the erosion rate of seabed continuously decreased in the study area in recent years. The wave-induced high-bottom shear stress zone mostly resulted in the different erosion on both sides of the mouth and the formation of erosion center in the nearshore area. Meanwhile, the interactions between hydrodynamics and delta erosion played an important role in the erosion-accumulation evolution pattern of the subaqueous delta off the abandoned Qingshuigou mouth of the Yellow River.

       

    /

    返回文章
    返回