| 人类活动对珠江伶仃洋余环流结构的影响研究：以洪季小潮为例 |
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| 引用本文： | 梅金亚,陈永平,储南洋,苏敏,刘培,姚鹏.人类活动对珠江伶仃洋余环流结构的影响研究：以洪季小潮为例[J].海洋学报,2023,45(2):27-41. |
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| 作者姓名： | 梅金亚 陈永平 储南洋 苏敏 刘培 姚鹏 |
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| 作者单位： | 1.河海大学 水文水资源与水利工程科学国家重点实验室，江苏 南京 210098 |
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| 基金项目： | 国家自然科学基金（51979076，51809296）；中央高校基本科研业务费专项资金（B200202057，2019B04514）；中国博士后科学基金（2021M70378）；大连理工大学海岸和近海工程国家重点实验室开放基金（LP2207）；广州市南沙区水务局科技项目（2022-263）。 |
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| 摘 要： | 近20 a来，受高强度人类活动影响，珠江伶仃洋滩槽已发生远超自然过程的异变，其河口动力结构必然发生响应，影响物质输运过程。本研究利用三维水动力数值模型，探讨了伶仃洋河口小潮期余环流结构的变化特征及原因。结果表明：近20 a来伶仃洋底层余流强度提高，沿深槽上溯时向中滩偏转，易引起泥沙汇聚于此。中滩存在表层向西，底层向东的横向余环流结构，主要由非线性对流项和科氏力项驱动。中滩大规模采砂后引起对流项变化，造成余环流结构东移，表、底层余流增强，可加快表底层物质交换。西槽内存在表层向海、底层向陆的纵向余环流结构，主要由正压和斜压梯度力驱动。受浚深影响，向陆斜压梯度力和非线性对流项均增强，引起表层余流减小22%，而底层增大24%，这将削弱小潮期西槽内水体交换能力，即减慢物质输出，易造成西槽淤积、水环境恶化等影响。研究成果对研究人类活动干扰下的河口余环流结构及物质输运响应具有一定借鉴意义。
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| 关 键 词： | 纵向余环流 横向余环流 人类活动 伶仃洋河口 三维数值模型 |
| 收稿时间： | 2022-04-23 |
Human effects on the residual circulations in the Lingding Bay,Zhujiang River Estuary: a case study of neap tides during flood season |
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| Affiliation: | 1.State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, China2.College of Harbor Coastal and Offshore Engineering, Hohai University, Nanjing 210098, China3.Zhuhai UM Science & Technology Research Institute, Zhuhai 519031, China4.The Pearl River Hydraulic Research Institute, Guangzhou 510611, China5.State Key Laboratory of Coastal and Office Engineering, Dalian University of Technology, Dalian 116024, China |
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| Abstract: | Over the past 20 years, the morphology of the Lingding Bay in the Zhujiang River Estuary has undergone anomalous changes, which is far beyond natural processes due to the influence of high intensity human activities. Hence, the resulted estuarine dynamics have inevitably influenced as well as the material transport processes. In this study, a three-dimensional model has been setup to explore the changes of residual circulation pattern in the Lingding Bay over the past 20 years and their potential impacts. The results show that the bottom residual flow along the East and West channels is turned towards the Middle Shoal area, which promotes the sedimentation there. The lateral residual circulation in the Middle Shoal depicts a layered structure of the surface to the west and the bottom to the east, mainly driven by the non-linear advection term. The large-scale sand mining in the Middle Shoal has resulted in the eastward shift of the residual circulation structure and the enhancement of the surface and bottom residual currents, which can accelerate the exchange of material between the surface and bottom layers. A longitudinal residual circulation structure exists in the West Channel with the surface layer seaward and the bottom layer landward, driven mainly by barotropic and baroclinic pressure gradient forces. Due to the effect of dredging depth, both the landward baroclinic pressure gradient force and the non-linear convection term are enhanced, the seaward-direction surface residual flow reduces by 22%, while the landward-direction bottom residual flow increases by 24%, which will weaken the exchange capacity of the water body in the western trough during the neap tide period, i.e. slow down the material export, resulting in the siltation of the western trough and the weakening of the water environment. This study can provide implications for understanding of estuarine residual circulation as well as material transport under anthropogenic disturbance. |
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