Collaborative Research: Turbulent fluxes and boundary layer structure due to near-shore internal tides

合作研究：近岸内潮汐引起的湍流通量和边界层结构

• 批准号: 0824928
• 负责人: Jonathan Nash
• 金额: $ 30.37万
• 依托单位: Oregon State University
• 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: 2009-01-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0824928&HistoricalAwards=false
• 关键词: Collaborative; Research; Turbulent; fluxes; boundary

Internal tides are a generic feature of near shore flows, playing a fundamental role in the ecology, biogeochemistry, and sedimentary environment of the near shore. For example, on coral reefs, turbulent mixing, as modified by stratification, can determine the strength of coupling between the water column and the reef. In a like fashion, internal waves can also be important to such environments as kelp forests where they may be a critical means of cross-shore transport of larval organisms. Thus, understanding the behavior of internal waves and the mixing they produce in shallow water is a fundamental problem in coastal oceanography. More generally, the high spatial and temporal resolution of physical measurements will result in a unique data set capable of linking large and small-scale physical processes on the continental slope and shelf. This data will be useful in developing more accurate parameterizations of boundary layer turbulence and mixing. In particular, it will be able to determine simple empirical relations like those found in lab experiments and computations but valid at field scales, that can be used in a wide range of circulation models. This project will measure Reynolds stresses, turbulent buoyancy fluxes, and turbulence dissipation rates in the near shore bottom boundary layer in the presence of shoaling internal tides and surface waves. Taking advantage of the capabilities of the Kilo Nalu Observatory operated by the University of Hawaii, these measurements will be made in 20 meters of water on the south shore of Oahu. Like many inner shelf regions, the proposed field site provides an environment in which both internal tides and surface waves are common. All the turbulence instruments will be cabled to shore, allowing acquisition of the data at high rates not limited by power or memory. Leveraging ongoing observations of surface waves and internal tides, the turbulence measurements will be supplemented by mean flow measurements made with ADCPs, thermistor and salinity sensor chains, and wave/tide gauges. The field measurements will yield a high quality turbulence data set, made in a setting for which we will have a fairly complete overall description of the mean flow. The field program will involve graduate and undergraduate students from University of Hawaii and Stanford University. These will be involved in all phases of the work, in particular, the scientific diving operations needed to install and recover the instrument suite. This group will include several women Ph. D. students and postdocs at both institutions.

内潮是近岸海岸流的一个普遍特征，对近岸海岸的生态、地球化学和沉积环境起着重要作用。例如，在珊瑚礁上，湍流混合，由于分层的修改，可以确定水柱和珊瑚礁之间的耦合强度。在类似的方式，内波也可以是重要的海藻森林等环境中，他们可能是一个关键的手段，跨海岸运输的幼虫生物。因此，了解内波的行为和它们在浅水中产生的混合是海岸海洋学的一个基本问题。更一般地说，物理测量的高空间和时间分辨率将产生一套独特的数据，能够将大陆坡和大陆架上的大规模和小规模物理过程联系起来。这些数据将有助于发展更精确的边界层湍流和混合的参数化。特别是，它将能够确定简单的经验关系，如在实验室实验和计算中发现的，但在现场尺度有效，可用于广泛的环流模型。该项目将测量在变浅内潮和表面波存在的情况下，近海岸底部边界层中的雷诺应力、湍流浮力通量和湍流耗散率。利用夏威夷大学基洛纳鲁天文台的能力，这些测量将在俄勒冈州南海岸20米深的水中进行。像许多内陆架区域一样，拟议的现场提供了一个内潮和表面波都很常见的环境。所有湍流仪器都将通过电缆连接到海岸，允许以不受功率或存储器限制的高速率采集数据。利用对表面波和内潮的持续观测，湍流测量将由ADCP、热敏电阻和盐度传感器链以及波浪/潮汐测量仪进行的平均流量测量进行补充。现场测量将产生一个高质量的湍流数据集，在一个设置，我们将有一个相当完整的平均流的整体描述。该实地项目将涉及来自夏威夷大学和斯坦福大学的研究生和本科生。这些人员将参与工作的所有阶段，特别是安装和恢复仪器套件所需的科学潜水作业。这个小组将包括几个女博士。学生和博士后在两个机构。