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.

内部潮汐是近岸流的通用特征，在近海岸的生态学，生物地球化学和沉积环境中发挥了基本作用。例如，在珊瑚礁上，通过分层修改的湍流混合可以确定水柱和珊瑚礁之间的耦合强度。以类似的方式，内部波浪对于海带森林等环境也可能很重要，在海带森林中，它们可能是幼虫生物跨岸运输的关键手段。因此，了解内部波的行为及其在浅水中产生的混合是沿海海洋学的一个基本问题。更一般而言，物理测量的高空间和时间分辨率将导致一个独特的数据集，能够将大陆坡度和架子上的大型和小规模的物理过程链接起来。该数据将有助于开发边界层湍流和混合的更准确的参数化。特别是，它将能够确定简单的经验关系，例如在实验室实验和计算中发现的，但在田间尺度上有效，可以在广泛的循环模型中使用。该项目将在存在浅滩的内部潮汐和表面波的情况下，测量雷诺应力，湍流浮力通量以及近岸底部边界层的湍流耗散率。利用夏威夷大学运营的Kilo Nalu天文台的能力，这些测量将在瓦胡岛南岸20米的水中进行。像许多内部架子区域一样，所提出的现场位点提供了一个环境，其中内部潮汐和表面波很常见。所有的湍流仪器将被电缆用于岸上，从而使数据以不受电源或内存限制的高速率获取。利用表面波和内部潮汐的持续观察，将通过用ADCP，热敏电阻和盐度传感器链以及波/潮汐仪进行的平均流量测量来补充湍流测量值。现场测量结果将产生高质量的湍流数据集，在该设置中，我们将对平均流量进行相当完整的总体描述。现场计划将涉及夏威夷大学和斯坦福大学的研究生和本科生。这些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操作。该小组将在两个机构中包括几个女性博士学位和博士后。