Modelling Wave-Driven Setup

摘要：在这项研究中，伍兹霍尔海洋研究所的科学家将开发并验证影响海岸线演变的流体和沉积物过程的模型，这些模型可以持续数天至数月。波浪动量通量（辐射应力）的梯度驱动近岸环流，而近岸环流反过来又驱动沉积物的输运。近岸环流的一个重要方面是波浪驱动的装置，它是靠近海岸线的平均水位的高度。1997年在北卡罗莱纳的Duck附近以及2000年和2003年在加州的La Jolla附近进行了观测。这些研究表明，先前基于海浪产生的陆上波浪能量的线性理论对跨海岸辐射应力的估计比观测到的要小。本研究将扩展一个数值模型，包括四个先前被忽略的过程：波辊、底部应力、波非线性和次重力波反射。然后将该模型的预测结果与现有的实地和实验室观测结果进行比较。流动垂直剖面的实验室观测将用于比较波能和辐射应力的线性和非线性表达式。如果非线性被证明是重要的，深度平均非线性表达式将被检查并纳入设置模型。此外，将使用准三维近岸社区和Delft3D模型的模拟来研究岸线水深不均匀性对波浪驱动装置的重要性。在风暴期间，波浪驱动装置可以将密封水平提高1米以上。在卡特里娜飓风期间，风暴潮和波浪组合造成的洪水破坏可能给社会造成重大损失。在这项研究中开发的模型可能对负责沿海洪水预测的沿海管理人员有用。这项研究构成了博士论文的基础，其结果将为新英格兰地区基于互联网的本科课程提供材料。

ABSTRACTOCE-0622844In this study, scientists at Woods Hole Oceanographic Institution will develop and validate models for the fluid and sediment processes that affect the evolution of the shoreline over periods of days to months. Gradients in wave momentum fluxes (radiation stresses) drive the near-shore circulation which in turn drives sediment transport. One important facet of the near-shore circulation is wave-driven setup, which is an elevation of mean water levels near the shoreline. Observations of setup were made in 1997 near Duck, North Carolina and in 2000 and 20003 near La Jolla, CA. These studies have shown that prior estimates of the cross-shore radition stress, which were based on a linear theory of onshore wave energy from sea swell, are smaller than what is observed. This study will extend a numerical model to include four previously neglected processes: wave rollers, bottom stress, wave nonlinearities, and infragravity wave reflection. The predictions of that model will then be compared with existing field and laboratory observations.Laboratory observations of the vertical profile of flows will be used to compare linear and nonlinear expressions for wave energy and radiation stress. If nonlinearities are shown to be important, depth-averaged nonlinear expressions will be examined and incorporated in the setup models. Additionally, the importance of alongshore bathymetric inhomogenities to the wave-driven setup will be examined using simulations of the quasi three-dimensional NearShore Community and Delft3D models.During storms, wave-driven setup has been observed to increase the seal level more than a meter. As became clear during Hurricane Katrina, flood damage by a combination of storm surge and wave setup can result in a significant cost to society. The model that is being developed in this study could be useful to coastal managers who are tasked with the prediction of coastal flooding. This study forms the basis of a PhD dissertation and results will provide material for internet-based undergraduate classes in New England.