长江口潮滩高分辨率波流耦合模型

A coupled wave-flow model at tidal flats in the Yangtze Estuary

中文关键词:  Delft3D  潮滩  降尺度模型  非线性波流耦合

英文关键词:Delft3D  tidal flats  downscaling model  nonlinear wave-current coupling

中文摘要:

      海岸带潮滩地区在潮汐的影响下呈现出复杂的地貌形态和波浪-水流的相互作用。建立高分辨率的潮滩波流耦合模型，以模拟潮滩中的精细波浪水动力过程，对于海岸防护设施设计和滨海湿地生态修复工程至关重要。本文以长江口南汇潮滩为研究区域，通过提出基于无人机RTK数据的潮滩高程反演技术，构建考虑潮滩干湿界面交替变化的波浪-水流耦合方法，开展潮滩波浪和水流现场观测等手段，借助Delft3D软件包建立了长江口潮滩高分辨率波流耦合模型。该模型嵌套长江口大尺度模型和潮滩小尺度模型，整合了海图水深数据、船测水深数据以及无人机高程反演数据，模型的边界条件包括天文潮汐、风场、径流和二维波浪谱等时序数据。研究结果表明，该模型不仅成功重现长江口水位、波浪和水流等关键参数，还能够精准模拟潮滩上的非线性波流耦合过程，模型模拟的潮滩水位、流速流向、波高等方面与实际观测数据具有较强的一致性。该模型不仅可为海岸水动力-结构相互作用模型提供边界条件，还能为滨海湿地生态修复和河口海岸管理提供精准的水动力支持。

英文摘要:

      Tidal flats areas in the coastal zone present complex geomorphological morphology and wave-current coupling under the influence of tides. The establishment of a high-resolution wave-current coupling model for tidal flats to simulate the fine wave hydrodynamic processes in tidal flats is crucial for the design of coastal protection facilities and ecological restoration projects in coastal wetlands. In this paper, a high-resolution wave-current coupling model of the tidal flats in the Yangtze River estuary is established with the help of Delft3D software package by proposing the tidal flats elevation inversion technique based on the RTK data from an unmanned aerial vehicle (UAV), constructing a wave-current coupling method considering the alternating changes of the dry and wet interfaces of the tidal flats, and carrying out on-site observations of the tidal flats waves and currents. The downscaled model is nested with the large-scale model of the Yangtze River estuary and the small-scale model of the tidal flats, and integrates the bathymetry data from charts, bathymetry data from ship surveys, and elevation inversion data from unmanned aerial vehicles (UAVs), and the boundary conditions of the model include the astronomical tides, wind, runoff, and two-dimensional wave spectra and other time series data. The results show that the model not only successfully reproduces the key parameters of water level, wave and current in the Yangtze River estuary, but also accurately simulates the nonlinear wave-current coupling process on the tidal flats, and the simulated water level, current velocity, wave height and so on on the tidal flats have a strong consistency with the actual observation data. The model not only provides boundary conditions for the coastal hydrodynamic-structural interaction model, but also provides accurate hydrodynamic support for the ecological restoration of coastal wetlands and estuarine coastal management.