Responses of tidal-current-asymmetry to shoreline variation in radial sand ridges in the South Yellow Sea
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摘要: 近岸地区的潮流不对称影响着沉积物输运和地貌改变。南黄海辐射沙洲海域潮动力强且水动力环境复杂，分析研究该海域潮流不对称性对海岸带资源的开发与保护有长远意义。本文基于Delft3D模型模拟1984年、2014年不同岸线条件下辐射沙洲海域的潮汐潮流运动，结合调和分析与偏度理论，分析刻画了不同岸线条件下潮流不对称性的空间分布特征。研究表明：辐射沙洲海域地形主导的涨落潮流速不对称性（PCA）以涨潮占优为主导；涨落憩历时不对称性（SWA）则以涨憩历时短为主导。二者皆主要受半日分潮（M2、S2）和浅水分潮（M4、MS4）的非线形作用影响。1984–2014年岸线变动后PCA正负性不变，但强度进一步增大，最大变幅可达25%；而
$ {\gamma }_{\mathrm{S}\mathrm{W}\mathrm{A}} $ 减小，最大减幅可达20%，SWA在辐射沙洲海域涨憩历时短的趋势增加。Abstract: Tidal-current-asymmetry (TCA) influences sediment transport and geomorphologic changes. It is of paramount importance to understand the current asymmetry in this area in context of a long-term scale with consideration of development and protection of the coastal resources. The radial sand ridges (RSR) in the South Yellow Sea is patterned with strong tidal forcing and complex hydrodynamic environment. This paper simulated tidal current field in the RSR based on the Delft3D model and used combined harmonic analysis and skewness theory to analyze the spatial distribution of the TCA under varied shoreline conditions. The results show that peak-current-asymmetry (PCA) in the RSR is mostly flood-dominant and slack-water-asymmetry (SWA) also shows positive, meaning the flooding duration is shorter than the ebbing duration. Both the positively-dominant PCA and negatively-dominant SWA are mainly affected by the nonlinear interactions between the semidiurnal diurnal tides (M2, S2) and shallow water tides (M4, MS4). As the shoreline gradually moves towards sea during 1984 to 2014, although the nature of$ {\gamma }_{\mathrm{P}\mathrm{C}\mathrm{A}} $ remains, the magnitude of which increases by up to 25%. Meanwhile,$ {\gamma }_{\mathrm{S}\mathrm{W}\mathrm{A}} $ decreases by up to 20%, which intensifies its shorter-flooding-duration pattern in the core area of the RSR. -
图 1 Delft3D水动力模型的网格及1984年及2014年岸线图（a），黄海海域地形图（b）及辐射沙洲地形图（c）
Fig. 1 Grid domain of Delft3D hydrodynamic model and shorelines in 1984 and 2014 (a), bathymetry of the Yellow Sea (b), and bathymetry of the radial sand ridges (c)
图 2 与 PCA（a，b）和SWA（c，d）相关的流速过程线示意图
Fig. 2 Schematic diagram of tidal current time series in context of PCA (a, b) and SWA (c, d)
图 3 不同公式计算所得PCA（a）和SWA（b）散点图
红点为模型输出全局各位置处偏态值，落在蓝线上各点的横纵坐标值相等
Fig. 3 Scatter diagrams of PCA (a) and SWA (b) calculated by different formulas
The red point is the skewness value at each positlon of the model output globally. The horizonal and vertical values of each point on the blue une are equal
图 4 1984年涨急、落急流场分布（a，b）和2014年相较1984年的涨急、落急流速变化（c，d）
Fig. 4 Distribution of flow field at flood and ebb in 1984 (a, b), and changes of flow field at flood and ebb in 2014 as compared to 1984 (c, d)
图 5 2014年PCA分布（a），2014年较1984年PCA变化分布（b），2014年PCA最大贡献项空间分布（c）及1984年PCA最大贡献项（d）空间分布
Fig. 5 Distribution of PCA in 2014 (a), distribution of PCA-changes in 2014 compared to 1984 (b), spatial distribution of the largest contributors to PCA in 2014 (c), and spatial distribution of the largest contributors to PCA in 1984 (d)
图 6 2014年SWA分布（a），2014年较1984年SWA变化分布（b），2014年SWA最大贡献项空间分布（c）及1984年SWA最大贡献项空间分布（d）
Fig. 6 Distribution of SWA in 2014 (a), distribution of SWA-changes in 2014 compared to 1984 (b), spatial distribution of the largest contributor to SWA in 2014 (c), and spatial distribution of the largest contributor to SWA in 1984 (d)
图 7 2014年PCA各项分布（a，b）和2014年较1984年PCA各项变化分布（c，d）
Fig. 7 Distribution of PCA contributors in 2014 (a, b) and distribution of PCA contributors changes in 2014 compared to 1984 (c, d)
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[1] Toublanc F, Brenon I, Coulombier T, et al. Fortnightly tidal asymmetry inversions and perspectives on sediment dynamics in a macrotidal estuary (Charente, France)[J]. Continental Shelf Research, 2015, 94: 42−54. doi: 10.1016/j.csr.2014.12.009 [2] Friedrichs C T, Aubrey D G. Non-linear tidal distortion in shallow well-mixed estuaries: a synthesis[J]. Estuarine, Coastal and Shelf Science, 1988, 27(5): 521−545. doi: 10.1016/0272-7714(88)90082-0 [3] Nidzieko N J. Tidal asymmetry in estuaries with mixed semidiurnal/diurnal tides[J]. Journal of Geophysical Research, 2010, 115(C8): C08006. [4] Nidzieko N J, Ralston D K. Tidal asymmetry and velocity skew over tidal flats and shallow channels within a macrotidal river delta[J]. Journal of Geophysical Research, 2012, 117(C3): C03001. [5] Song Dehai, Wang Xiaohua, Kiss A E, et al. The contribution to tidal asymmetry by different combinations of tidal constituents[J]. Journal of Geophysical Research, 2011, 116(C12): C12007. doi: 10.1029/2011JC007270 [6] 李谊纯. 一个潮流不对称计算方法及其在北仑河口的应用[J]. 海洋工程, 2014, 32(4): 110−116.Li Yichun. A method of quantifying tidal current asymmetry and its application in the Beilun River estuary[J]. The Ocean Engineering, 2014, 32(4): 110−116. [7] Gong Wenping, Schuttelaars H, Zhang Heng. Tidal asymmetry in a funnel-shaped estuary with mixed semidiurnal tides[J]. Ocean Dynamics, 2016, 66(5): 637−658. doi: 10.1007/s10236-016-0943-1 [8] Guo Leicheng, Brand M, Sanders B F, et al. Tidal asymmetry and residual sediment transport in a short tidal basin under sea level rise[J]. Advances in Water Resources, 2018, 121: 1−8. doi: 10.1016/j.advwatres.2018.07.012 [9] 陈婷, 张蔚, 季小梅, 等. 长江口潮流不对称时空分布特征[J]. 长江科学院院报, 2021, 38(4): 7−12,18. doi: 10.11988/ckyyb.20200393Chen Ting, Zhang Wei, Ji Xiaomei, et al. Spatial-temporal characteristics of tidal current asymmetry in the Yangtze River estuary[J]. Journal of Yangtze River Scientific Research Institute, 2021, 38(4): 7−12,18. doi: 10.11988/ckyyb.20200393 [10] 任美锷. 江苏省海岸带和海涂资源综合调查报告[M]. 北京: 海洋出版社, 1985: 120−133.Ren Meie. Report for Comprehensive Investigation on Recourses of Coastal Zones and Tidal Flats in Jiangsu Province[M]. Beijing: China Ocean Press, 1985: 120−133. [11] 袁金金, 冯曦, 冯卫兵. 辐射沙洲地形对南黄海潮汐过程的影响[J]. 科学通报, 2018, 63(27): 2904−2918. doi: 10.1360/N972018-00125Yuan Jinjin, Feng Xi, Feng Weibing. Effects of radial sand ridges on tidal process in the South Yellow Sea[J]. Chinese Science Bulletin, 2018, 63(27): 2904−2918. doi: 10.1360/N972018-00125 [12] 钱沛, 冯曦, 冯卫兵, 等. 辐射沙洲海域潮汐不对称对岸线变化的响应[J]. 水利水运工程学报, 2020(3): 51−60. doi: 10.12170/20190901002Qian Pei, Feng Xi, Feng Weibing, et al. Response of tidal asymmetry to coastline changes in radial sand ridges sea area[J]. Hydro-Science and Engineering, 2020(3): 51−60. doi: 10.12170/20190901002 [13] Feng Xi, Feng Hui. On the role of anthropogenic activity and sea-level-rise in tidal distortion on the open coast of the Yellow Sea Shelf[J]. Journal of Geophysical Research, 2021, 126(3): e2020JC016583. [14] Feng Xi, Feng Hui, Li Huichao, et al. Tidal responses to future sea level trends on the Yellow Sea shelf[J]. Journal of Geophysical Research, 2019, 124(11): 7285−7306. doi: 10.1029/2019JC015150 [15] Pawlowicz R, Beardsley B, Lentz S. Classical tidal harmonic analysis including error estimates in MATLAB using T_TIDE[J]. Computers & Geosciences, 2002, 28(8): 929−937. -
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