Collaborative Research: Tidal internal waves that propagate along the coast: Determining how they are generated and how far they travel

潮汐内波是表层潮汐与地形相互作用的产物，其产生、传播和消散是海洋潮汐能量的重要途径。内潮可构成大陆架上的主要能源，可导致孤子产生、湍流混合和跨陆架交换等过程，对运输、生物生产力和近岸污染有广泛影响。这项研究将探索内潮是如何在陆架断裂附近转化为沿海岸传播的，以及它们通过向近海辐射部分能量而衰减的速度。在深海中，内潮通常表现为低垂直模波，然而，在靠近大陆架断裂的地方，它们可能会以“泄漏”(超惯性)斜压海岸困波和边缘波的形式出现。这些模式结构是研究得很好的亚惯性海岸捕获波的超惯性类似物，有一个分量沿着陆架断裂辐射。然而，它们与亚惯性波的区别在于它们在近海表现出重合辐射(即“泄漏”)。这项研究的目的是更好地了解靠近海岸边缘的内潮的性质，在那里，泄漏斜压困住的内潮的存在可能有助于潮汐能量沿海岸的变化和传播。这项研究将考虑当地天文潮汐和远程入射的深海内潮汐对这些波的强迫。该方法将包括理想化、线性、二维(跨岸)分析；对海岸对本地和远程强迫的响应的理想化、三维、非线性数值模拟；以及一套现实的数值模拟，以调查由于本地和远程强迫而导致的美国西海岸的泄漏被困的内部潮汐能量。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Tidal internal waves arise from the interaction of the surface tide with topography, with their generation, propagation and dissipation forming a key pathway for tidal energy in the ocean. Internal tides can constitute a dominant energy source on continental shelves, where they can lead to processes such as soliton generation, turbulent mixing and cross shelf exchange, with wide ranging implications for transport, biological productivity and near-shore pollution. This study will explore how internal tides are transformed near the shelf break to propagate along the coast and how quickly they decay by radiating some of their energy offshore.In the deep ocean internal tides usually manifest as low vertical mode waves, however, close to the continental shelf break they may take the form of "leaky" (superinertial) baroclinic coastal trapped waves and edge waves. These modal structures are superinertial analogues to the well studied subinertial coastal trapped waves, having a component that radiates along the shelf break. However, they are distinguished from subinertial waves by exhibiting coincident radiation offshore (i.e. "leaking"). The goal of this study is to better understand the nature of internal tides close to the coastal margin, where the presence of leaky baroclinic trapped internal tides may contribute to the along shore variability and propagation of tidal energy. The study will consider the forcing of these waves by both the local astronomical tide, and by remotely incident deep ocean internal tides. The approach will include idealized, linear, two-dimensional (cross-shore) analyses; idealized, three-dimensional, nonlinear numerical simulations of the coastal response to local and remote forcing; and a suite of realistic numerical simulations to investigate leaky trapped internal tide energy along the U. S. West coast due to local and remote forcing.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.