Collaborative Research: The Dynamics of Shoaling and Breaking Nonlinear Internal Waves and their Transport, Dispersion and Buoyancy and Momentum Balances

内波是在分层水柱的两层之间形成的波，在大多数大陆架地区被观察到向海岸线传播。当这些波浪进入水深约为波浪振幅一半的水域时，由于底部摩擦，这些波浪会变浅或变慢，它们与底部的相互作用导致这些波浪发生转变。跨岸运输和营养物与浮游生物混合的观测表明，非线性内波（NLIWs）在一些内陆架底栖生物群落的维持中起着关键作用。然而，跨岸输送长度尺度、扩散速率和浮力、动量和能量通量，以及这些波对沿海环流和生态系统的潜在重要影响尚未量化。俄勒冈州立大学和北卡罗来纳大学的海洋学家在伍兹霍尔海洋研究所的支持下，将采用观测和数值相结合的方法，量化浅滩NLIWs的输送、扩散、浮力和动量通量以及通量散度，并确定它们对马萨诸塞湾低频环流和密度场的影响。他们的实地观察将包括部署一个系泊阵列来量化非线性内波通量，快速船载调查来研究单个波从其产生点到浅滩区域，直到它们在海岸附近消亡的演变，以及染料注入和船载跟踪来量化跨岸运输和扩散速率的规模。除了现场观测外，还将使用“最先进的”自适应网格、非流体静力学数值模型来模拟非线性内波的产生和演化，将数值输出与现场观测结果进行比较，并了解这些波的详细三维演化。研究这一过程将客观地评估NLIWs相对于沿海海洋其他物理过程的重要性。了解在沿海海洋中运输和分散水性物质（如营养物、污染物、浮游生物）的机制是沿海物理海洋学研究的一个高度优先的目标，并可对环境管理产生直接影响。

Internal waves, which are waves formed between two layers of a stratified water column, are observed to propagate towards the coastline in most continental shelve regions. As these waves shoal, or are slowed by bottom friction, when entering into water depths of approximately one-half of the wave amplitude, their interaction with the bottom causes these waves to undergo transformations. Observations of across-shore transport and nutrient and plankton mixing suggest that nonlinear internal waves (NLIWs) play a critical role in the maintenance of some inner shelf benthic communities. However, the across-shore transport length scales, the dispersion rates and the fluxes of buoyancy, momentum and energy, and, thus, the potentially important influence of these waves on coastal circulation and ecosystems, have not yet been quantified. Oceanographers from Oregon State University and the University of North Carolina, with support from the Woods Hole Oceanographic Institute, will use a combined observational and numerical approach to quantify transport, dispersion, buoyancy and momentum fluxes, and flux divergences of shoaling NLIWs and determine their influence on the low-frequency circulation and density field in Massachusetts Bay. Their field observations will include deployments of a mooring array to quantify nonlinear internal wave fluxes, rapid shipboard surveys to study the evolution of individual waves from their generation point, through the region of shoaling, and to their demise near the coast, and dye injections and shipboard tracking to quantify scales of across-shore transport and rates of dispersion. In addition to field observations, a 'state-of-the-art', adaptive grid, nonhydrostatic, numerical model will be used to simulate nonlinear internal wave generation and evolution to compare the numerical output with the field observations and understand the detailed, three-dimensional evolution of these waves. Studying this process will provide an objective assessment of the significance of NLIWs relative to other physical processes in the coastal ocean. Understanding the mechanisms which transport and disperse water-borne materials (e.g., nutrients, pollutants, plankton) in the coastal ocean is a high priority objective for coastal physical oceanographic research and can have direct influence on environmental management.