南黄海辐射沙洲潮流不对称性对岸线变动的响应  

Responses of tidal-current-asymmetry to shoreline variation in radial sand ridges in the South Yellow Sea

作　　者：冯曦 丁志伟 冯辉 张蔚[1] 储鏖 张驰 Feng Xi;Ding Zhiwei;Feng Hui;Zhang Wei;Chu Ao;Zhang Chi(College of Harbor,Coastal and Offshore Engineering,Hohai University,Nanjing 210098,China)

机构地区：[1]河海大学港口海岸与近海工程学院,江苏南京210098

出　　处：《海洋学报》2022年第6期1-9,共9页

基　　金：国家自然科学基金(519056611);国家自然科学基金长江水科学联合基金项目(U2040203)。

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(M_(2)、S_(2))和浅水分潮(M_(4)、MS_(4))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γ_(SWA)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。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 consid-eration 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 negativelydominant SWA are mainly affected by the nonlinear interactions between the semidiurnal diurnal tides(M_(2),S_(2))and shallow water tides(M_(4),MS_(4)).As the shoreline gradually moves towards sea during 1984 to 2014,although the nature ofγ_(PCA)remains,the magnitude of which increases by up to 25%.Meanwhile,γ_(SWA)decreases by up to 20%,which intensifies its shorter-flooding-duration pattern in the core area of the RSR.

关 键 词：潮流不对称 峰值电流不对称 松弛水不对称 辐射沙洲 岸线变迁 

分 类 号：P737.17[天文地球—海洋地质]