| 钟子悦,向波,余明辉,刘书宝.伶仃洋河口枯季径-潮-盐-悬沙动力特征对海床地形异变响应[J].水利学报,2025,56(4):477-487 |
| 伶仃洋河口枯季径-潮-盐-悬沙动力特征对海床地形异变响应 |
| Response of river-tide-salt-suspended sediment dynamics to seabed topographic abnormality during dry season in the Lingdingyang Bay |
| 投稿时间：2024-06-23 |
| DOI：10.13243/j.cnki.slxb.20240389 |
| 中文关键词: 伶仃洋 悬沙垂向分布 层化 河口潮动力 |
| 英文关键词: Lingdingyang Bay vertical suspended sediment distribution stratification estuarine tidal dynamics |
| 基金项目:国家自然科学基金项目（12372385） |
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| 中文摘要: |
| 1974—2016年，由于围垦工程、航道疏浚工程、河口采砂等人类活动影响，伶仃洋河口岸线与地形发生异常变化，径潮动力、盐淡水混合状态和悬沙分布特征随之发生变化，有必要研究地形异变后的径-潮-盐-悬沙动力变化特征以及这种特征对地形异变的响应机制。因此，本文分析了2016年枯季伶仃洋部分测站的流速悬沙盐度实测资料，基于EFDC软件建立了三维径-潮-盐-悬沙动力数学模型，研究岸线与地形异变驱动下伶仃洋河口盐水层化与悬沙垂向分布变化规律。结果表明，岸线的收缩幅度增大、向海延伸与海床地形下切导致伶仃洋河口潮动力相对增强但逐步转型为强分层河口。涨潮期间水体盐度和悬沙浓度垂向混合较为均匀，落潮期间水体盐度分层明显，浮力通量在湍动能中的占比增大，为盐跃层提供能量；湍流混合变弱，抑制底部泥沙再悬浮，表征悬沙垂向分布不均匀程度的离散系数CV从0.51增大至1.02。在一个涨落潮周期内，CV与表征层化的总体Richardson数呈现滞后正相关响应关系。研究成果揭示了伶仃洋河口枯季盐水与悬沙输运的互馈影响关系，为伶仃洋水沙治理提供了科学依据。 |
| 英文摘要: |
| During the period of 1974-2016，due to the impacts of human activities like reclamation projects，channel dredging projects，and sand mining in the estuary，the shoreline and seabed topography of Lingdingyang Bay changed abnormally，and the characteristics of the distribution of river-tide-salt-suspended sediment changed accordingly. It is necessary to study the characteristics of river-tide-salt-suspended sediment dynamics after topographic anomalies and the response mechanism of such characteristics to seabed topographic anomalies. Therefore，this study analyzed the turbidity-salinity data of suspended sediment measured from stations in Lingdingyang Bay during the dry season of 2016，and established a three-dimensional mathematical model of runoff-tide-salt-suspended sediment dynamics based on EFDC software to study the changing mechanisms of salinity stratification and vertical distribution of suspended sediment in the mouth of the Lingdingyang Bay under the drive of anomalous changes of the shoreline and the topography. The results show that the increased convergence and seaward extension of the shoreline and the downcutting of the topography lead to a relative enhancement of the tidal dynamics of the Lingdingyang Bay. During flood tide，the water column salinity and suspended sediment concentration are mixed relatively uniformly in the vertical direction. During ebb tide，the water column salinity is stratified significantly，and the buoyancy item accounts for a larger proportion of the turbulent kinetic energy，which provides energy for the salinity stratification. The turbulent mixing is weakened，inhibiting the re-suspension of the bottom sediments and increasing the dispersion coefficient（CV）from 0.51 to 1.02，which characterizes the degree of non-uniformity in the vertical distribution of the suspended sediment. During a tidal cycle，CV exhibits a lagged positive correlation with the overall Richardson number that characterizes stratification. The results of this study revealed the mutual feed-influence relationship between saline water and suspended sediment transport in the estuary of Lingdingyang Bay during the dry season，and provide a scientific basis for the management of water and sediment in the Lingdingyang Bay. |
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