Collaborative Research: LES & Modeling of Turbulence on Shallow Shelves under Combined Langmuir, Tidal & Convective Forcing with Comparison to VADCP Observations

合作研究：LES

• 批准号: 0927054
• 负责人: Andres Tejada-Martinez
• 金额: $ 6.91万
• 依托单位: University of South Florida
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-15 至 2014-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0927054&HistoricalAwards=false
• 关键词: Collaborative; Research; LES; & Modeling

Intellectual Merit: Langmuir supercells (LSC), Langmuir circulations that engulf the entire water column during strong wind/wave forcing of shallow seas, were first identified in 2003 from vertical-beam acoustic Doppler current profiler measurements at the LEO15 cabled observatory off New Jersey. Similar measurements have been made more recently at the Navy's R2 tower on mid-shelf off the coast of Georgia, under different wind, wave and tidal forcing conditions. These unique data sets provide an opportunity, when combined with large-eddy simulations (LES) to investigate the interaction of several turbulence generating mechanisms in shallow seas. It is proposed to study the interaction between LSC, the tidally-forced bottom boundary layer, wave breaking and stratification (stable and unstable) from analysis of the LEO15 and R2 data sets and large-eddy simulation of LSC carefully guided by the observations. Once validated by comparison with the observations over the range of forcing ratios that characterize these data sets, the multi-process LES will allow exploration of non-dimensional forcing parameters outside this range, allowing assessment of the effect of LC on shelves other than those for which measurements exist. Simulations will be performed spanning parameter space. In traversing the parameter space, different turbulent regimes will be encountered such as Langmuir-dominated turbulence, convection-dominated turbulence and shear-dominated turbulence. Regime diagrams will help establish bulk forcing conditions for which LSC is dominant. Understanding of the interactions will lead to increased understanding of the dynamics of these various kinds of turbulence and to improved turbulence parameterizations for inclusion in large-scale coastal circulation models accounting for Langmuir turbulence. The modified parameterizations are expected to lead to improved predictions of vertical mixing on shallow shelves, ultimately leading to improved prediction of cross-shelf flows.Broader impacts: This project will result in improved shallow-water turbulence parameterizations accounting for wave-current interaction implemented within a number of widely used circulation models available to the general oceanography community. The proposed developments are focused in the coastal ocean where the effect of the bottom is important. Many continental shelves are biologically highly productive, for example the Bering Sea Shelf, one of the major United States fisheries. This research will increase understanding of the mechanisms controlling vertical mixing and cross shelf transport of biologically active materials and sediment. The parameterizations developed and the inclusion of important physics should improve the accuracy of models of coastal ocean flows at different resolution levels, ultimately proving important for coupled physical-chemical-biological models. This project will provide funding for a post-doctoral fellow who will train in multidisciplinary fields spanning fluid dynamics, physical oceanography, numerical methods and experimental methods. Dr. Tejada-Martínez, one of the co-PIs, is a scientist in an under-represented minority group. For outreach, Dr. Savidge participates yearly in training sessions for high school teachers through Skidaway?s local connections, and through research colloquia for pre-service teachers at Armstrong Atlantic State University in Savannah. Visual displays will be provided for the general public, adding to a computer-based interactive presentation BOTTOMS-UP in the Marine Education Center and Aquarium on Skidaway Island and on Jekyll Island, in conjunction with Savidge's planned HF-radar installation there. Important results from this modeling project will be incorporated in these developing displays. While details of modeling may be difficult to express to non-scientists, it will be possible to illustrate improvements in model performance during major wind-forcing events, and to emphasize the importance of such models in predicting larval and sediment transport in the nearshore coastal ocean that is of most interest to the general public.

智力优势：朗缪尔超级单体（LSC）是在浅海强风/波浪强迫期间吞没整个水柱的朗缪尔环流，于2003年首次在新泽西外的LEO 15有线观测站通过垂直波束声学多普勒海流剖面仪测量发现。最近，在不同的风、波浪和潮汐强迫条件下，在格鲁吉亚海岸外的中陆架上的海军R2塔也进行了类似的测量。这些独特的数据集提供了一个机会，当结合大涡模拟（LES），调查在浅海中的几个湍流生成机制的相互作用。建议通过对LEO 15和R2数据集的分析以及在观测指导下对LSC进行的大涡模拟来研究LSC、潮汐强迫底边界层、波浪破碎和层结（稳定和不稳定）之间的相互作用。一旦验证与强迫比的特征，这些数据集的范围内的观察比较，多过程LES将允许探索这个范围之外的无量纲强迫参数，允许评估的影响，LC货架上的其他测量存在。将在参数空间内进行模拟。在穿越参数空间时，会遇到不同的湍流状态，例如朗缪尔主导的湍流，对流主导的湍流和剪切主导的湍流。状态图将有助于建立LSC占主导地位的体积强迫条件。了解的相互作用将导致这些不同种类的湍流的动力学的理解，并改善湍流参数化纳入大型沿海环流模型占朗缪尔湍流。修改后的参数化，预计将导致改进的预测的垂直混合浅架，最终导致改进的预测跨架flows.Broader影响：这个项目将导致改进浅水湍流参数化占波流相互作用内实施了一些广泛使用的流通模式提供给一般海洋学界。拟议的发展集中在沿海海洋，因为海底的影响很重要。许多大陆架的生物生产力很高，例如白令海大陆架是美国的主要渔场之一。这项研究将增加对控制生物活性物质和沉积物的垂直混合和跨陆架迁移的机制的了解。参数化的发展和重要的物理学的列入应提高沿海洋流模型的准确性在不同的分辨率水平，最终证明耦合物理-化学-生物模型的重要性。该项目将为一名博士后研究员提供资金，他将在流体动力学、物理海洋学、数值方法和实验方法等多学科领域接受培训。Tejada-Martínez博士是一位代表性不足的少数群体的科学家。为了推广，萨维奇博士每年参加培训课程的高中教师通过斯基德韦？的地方联系，并通过研究座谈会的职前教师在阿姆斯特朗大西洋州立大学在萨凡纳。视觉显示将提供给公众，增加了一个基于计算机的互动演示自下而上在海洋教育中心和水族馆在斯基德韦岛和杰基尔岛，结合萨维奇的计划高频雷达安装在那里。从这个建模项目的重要成果将被纳入这些发展显示。虽然建模的细节可能很难表达给非科学家，它将有可能说明在主要的风力强迫事件模型性能的改进，并强调这种模型在预测幼虫和沉积物在近岸沿海海洋，这是最感兴趣的公众的重要性。