| 河口回水动力的演变过程及其影响机制 |
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| 引用本文： | 古俊豪,蔡华阳,杨昊,李博.河口回水动力的演变过程及其影响机制[J].海洋学报,2022,44(12):31-41. |
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| 作者姓名： | 古俊豪 蔡华阳 杨昊 李博 |
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| 作者单位： | 1.中山大学 海洋工程与技术学院 河口海岸研究所，广东 广州 510275 |
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| 基金项目： | 国家自然科学基金（51979296）；广州市科技计划（202002030452） |
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| 摘 要： | 河口回水区长度的时空演变对防洪、供水、航运等水资源高效开发利用具有重要指导意义。本文在经典河流回水理论的基础上考虑潮汐动力的影响，聚焦潮汐动力引起的回水效应问题，基于一维水动力解析模型，重新定义河口回水区上游界限（回水界），并以长江河口为例，探讨河口回水动力演变过程及其影响机制。结果表明:回水界距天生港的距离（即回水区长度）与上游流量、外海边界振幅分别具有显著的负相关和正相关关系，且基本为线性关系；回水界对径潮动力的响应比潮区界更为敏感，能有效表征河口感潮河段径潮动力格局演变；长江河口回水界位置具有明显的季节性差异，其春季和秋季回水界位于芜湖附近（春季和秋季分别距天生港419 km和367 km），冬季回水界位于感潮河段以上区域，夏季潮汐动力引起的回水效应基本可忽略；长江河口潮流因子和径潮相互作用因子控制的余水位梯度的季节性变化，是长江河口回水界位置变动的主导因素。
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| 关 键 词： | 回水长度 解析模型 潮汐动力 余水位 径潮相互作用 |
| 收稿时间： | 2022-05-06 |
The evolution of estuarine backwater dynamics and its underlying mechanism: a case study of the Changjiang River Estuary |
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| Institution: | 1.Institute of Estuarine and Coastal Research, School of Marine Engineering and Technology, Sun Yat-sen University, Guangzhou 510275, China2.State and Local Joint Engineering Laboratory of Estuarine Hydraulic Technology, Guangzhou 510275, China3.Guangdong Provincial Engineering Research Center of Coasts, Islands and Reefs, Guangzhou 510275, China4.Southern Laboratory of Ocean Science and Engineering (Zhuhai), Zhuhai 519000, China |
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| Abstract: | The spatio-temporal evolution of backwater influence length in estuaries is essential with regard to the sustainable water resources management in general, such as flood control, water supply, and shipping. In this study, based on the classical riverine backwater theory, we focus on the backwater effect caused by tidal dynamics, making use of a one-dimensional hydrodynamic analytical model to redefine the upstream boundary of the backwater zone (namely backwater limit) in estuaries. The model was subsequently applied to the Changjiang River Estuary to explore the evolution of estuarine backwater dynamics and its underlying mechanism. Results show that the distance from Tianshenggang to backwater limit (i.e., the backwater influence length) has a negatively linear correlation with the upstream river discharge and positively linear correlation with the tidal amplitude of seaward boundary, respectively. The response of the backwater limit to tidal river dynamics is more sensitive than that of the tidal limit, which can effectively characterize the evolution of the tidal river dynamics in tidal reach. The location of the backwater limit in the Changjiang River Estuary has apparent seasonal difference, being 419 km away from Tianshenggang during the spring and 367 km during autumn. The location is situated above the tidal reach during the winter, while the backwater effect caused by tidal dynamics during the summer is negligible. It was shown that the seasonal variations of residual water level slope induced by tide and tide-river interaction are the dominant factors for controlling the location of the backwater limit in the Changjiang River Estuary. |
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