CAREER: Shoaling of Non-Linear Internal Waves over Gentle Slopes: Wave-Scale Interactions and Dissipative Processes

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。非线性内波（NLIWs）是沿海海洋和湖泊中普遍存在的特征，是分层自然水体中由风和潮汐引发的大尺度能量级联的接收端。这些波浪将这种能量传输到100公里以外的缓坡（变浅）大陆架区域，并将其远程消散。最近在南中国海和新泽西大陆架进行的大规模野外实验为研究NLIW变浅过程提供了宝贵的信息。尽管如此，由于在空间和时间的限制，现场测量，一些关键问题的波浪浅滩仍然没有答案，即在相关的能量耗散机制，这是进一步复杂的大规模的波浪变换，由于可变水深。为此，小规模的数值模拟是势在必行的。该项目旨在使用一个完全非静力和非线性的并行谱四边形子域罚方法模型来数值研究缓坡上的NLIWs的浅水化。该模型使最大可能的尺度之间的分离波尺度和小尺度耗散过程中的波内部/足迹与后者的最佳分辨率，允许雷诺数尽可能接近海洋值。模拟将侧重于波浪尺度转换的基本物理，由于浅滩和三维湍流耗散动力学的NLIW诱导的海底边界层和地下被困再循环核心的影响。与上述站点的现场数据（包括来自南中国海的一组非常丰富的记录在案的NLIWs和捕获的岩心观测数据）进行密切比较，将建立模拟的一致性检查，充实测量的基本物理学，并为未来的部署提供指导。了解NLIW足迹和内部湍流耗散的物理学是关闭海洋和湖泊大规模能量预算的关键环节。此外，流场内被困的核心和NLIW引起的底栖边界层可以驱动强大的水平生物群/营养盐的运输和强烈的再悬浮的底部沉积的地球化学成分，分别。除了对波浪变浅的基本物理学进行更好的描述外，该项目还将为未来研究NLIWs内的流场如何直接与水下生态，声学和光学相互作用并影响水质提供基础。改进的参数化的颗粒再悬浮和近底/表面耗散，然后可以开发用于更大规模的模式和现场数据analysis.The密切的比较与南中国海现场数据将启动积极的长期合作之间的康奈尔大学和华盛顿大学。所有重要的数值结果将通过互联网数据库传播给海洋学界感兴趣的成员。受多域求解器中嵌入的先进数值方法的激励，一系列紧密相连的教育活动旨在重新考虑研究生/本科阶段的科学计算教育的当前范式，并促进高中学生进入科学和工程专业。从研究生课程开始，拟议的教育计划旨在培养海洋模型用户，这些用户虽然不是开发人员，但拥有强大的数值和海洋学专业知识，与尖端的计算方法保持一致。对科学计算的学士学位课程的重组将使本科生能够发现这一研究领域的潜力，并将其作为完成科学和工程研究的工具，从而为未来的数值建模者提供稳定的研究生队伍。一个为期一周的高中课程模块内波模拟湖泊将介绍不同的高中学生的观众计算建模作为替代传统的“湿实验室”和未来的研究在科学和工程应用计算的选择。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Nonlinear internal waves (NLIWs), ubiquitous features of the coastal ocean and lakes, are on the receiving end of an energy cascade initiated at large scales by the winds and tides in stratified natural water bodies. These waves transport this energy over 100km distances across gently sloping (shoaling) shelf regions and dissipate it remotely. Recent massive field-scale experiments in the South China Sea and the New Jersey Shelf have provided invaluable insight into the process of NLIW shoaling. Nonetheless, due to limitations of field measurements in space and time, a number of key questions on wave shoaling remain unanswered, namely in terms of the associated energy dissipation mechanisms, which are further complicated by the large-scale wave transformations due to variable bathymetry. To this end, small-scale numerical modeling is imperatively needed.The project aims at the use of a fully non-hydrostatic and nonlinear parallel spectral quadrilateral sub-domain penalty method model to numerically study shoaling of NLIWs over gentle slopes. The model enables the maximum possible scale separation between wave-scale and the small-scale dissipative processes in the wave interior/footprint with optimal resolution of the latter, allowing a Reynolds number as close as possible to the oceanic value. Simulations will focus on the basic physics of wave-scale transformations due to shoaling and their impact on the three-dimensional turbulent dissipative dynamics of the NLIW-induced benthic boundary layer and subsurface trapped recirculation cores. A close comparison with field data from the above sites (including a very richly documented set of observations from the South China Sea on NLIWs and trapped cores) will establish consistency checks for the simulations, flesh out the basic physics from the measurements and provide guidance for future deployments. Understanding the physics of turbulent dissipation in the NLIW footprint and interior is a crucial missing link in the closure of large-scale energy budgets in the ocean and lakes. Furthermore, the flow fields inside trapped cores and the NLIW-induced benthic boundary layer can drive powerful horizontal biota/nutrient transport and intense resuspension of bottom-lodged biogeochemical constituents, respectively. Beyond an enhanced description of the fundamental physics of wave shoaling, the project will offer the foundation for future investigations on how the flow fields within NLIWs directly interact with underwater ecology, acoustics and optics and impact water quality. Improved parameterizations of particulate re-suspension and near-bottom/surface dissipation may then be developed for use in larger-scale models and field data analysis.The close comparison with South China Sea field data will initiate an active long-term collaboration between Cornell and the University of Washington. All important numerical results will be disseminated to interested members of the oceanographic community via an internet database.Motivated by the advanced numerical methods embedded in the multi-domain solver, a tightly linked chain of educational activities seeks to initiate a reconsideration of the current paradigm in scientific computing education at the graduate/undergraduate level and to boost recruitment of high school students into science and engineering majors. Starting with graduate coursework, the proposed educational plan aims to create ocean model users who, although not developers, have a robust numerical and oceanographic expertise which is aligned with cutting edge computational methods. The restructuring of a sophomore-level course on scientific computing will allow undergraduate students to discover the potential of this research area and embrace it as a vehicle to complete their studies in the sciences and engineering, thereby establishing a consistent flux of future numerical modelers to the graduate ranks. A one-week high-school course module on internal wave simulation in lakes will introduce a diverse audience of high school students to computational modeling as an alternative to the traditional 'wet lab' and the option of future studies in applied computation in science and engineering.