Coastal Ocean Reynolds Stresses: Using New Methods with Long-Term Observations to Investigate Exchange and Evaluate Model Closures

沿海海洋雷诺强调：使用长期观测的新方法来研究交换和评估模型闭合

• 批准号: 1129348
• 负责人: Anthony Kirincich
• 金额: $ 17.8万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1129348&HistoricalAwards=false
• 关键词: Coastal; Ocean; Reynolds; Stresses; Using

Over the continental shelf, turbulence plays a primary role in distributing momentum through the water column. In the inner shelf, where surface and bottom boundary layers overlap, the magnitude and vertical structure of turbulent momentum flux (Reynolds stress) is thought to have a controlling influence on the circulation and exchange. The vertical structure of Reynolds stress in the coastal ocean is not well known, due in part to the difficulty in making unbiased estimates of stress in wavy environments. Recently developed analysis techniques have documented ways to account for wave-induced biases, allowing direct observations of coastal ocean stresses using the velocity profiles of commonly-deployed acoustic Doppler current profilers (ADCPs). This work proposes to use these methods to estimate the stresses present in a more than 10 year-long record of velocity profiles from the Martha's Vineyard Coastal Observatory (MVCO). Estimated stresses will be utilized, along with velocity, hydrographic, and wind observations, to examine how inner-shelf processes interact to determine the across-shelf exchange due to along-shelf winds, across-shelf winds, and surface gravity waves and relate variations in momentum transfer due to these processes to variations in across-shelf exchange. These estimates will be compared to predictions using common turbulence closure models for similar forcing conditions in both simple one- and two-dimensional or complex three-dimensional numerical model simulations. Intellectual Merit: In situ observations of turbulent stress profiles, traditionally the least accessible term in the momentum equations, are central to our ability to explain and predict coastal ocean dynamics. Using the long-term dataset, this work will separate the incremental effects of wind or wave forcing on Reynolds stresses, examining the dependence of the across-shelf circulation on the stress. Comparing these observations to predictions from numerical models will provide a powerful new tool to evaluate closure methods, enabling more accurate predictions of how stress-causing processes interact to drive circulation when such measurements are not available. The primary data product of the analysis, stress profiles estimated from MVCO's long-term velocity dataset, will be archived and served on the Observatory's website, and therefore available as a community data product for future research. Broader Impacts: The mechanisms that control the across-shelf exchange of water masses and nutrients control the productivity of the coastal ocean as well as the dispersal or retention of planktonic larvae and pollutants. The additional knowledge of turbulent stresses and their use in evaluating model parameterizations offer, potentially, a more precise understanding of the dynamics of the inner shelf and across-shelf exchange then has previously been possible, allowing exchange-dependent processes to be studied and modeled with increased accuracy. Results will be disseminated directly into the classroom via teaching and ongoing outreach programs.

在大陆架上，湍流在水柱中分配动量方面起着主要作用。在大陆架内部，表面和底部边界层重叠，湍流动量通量（雷诺应力）的大小和垂直结构被认为是有控制的环流和交换的影响。 在沿海海洋雷诺应力的垂直结构是不为人所知的，部分原因是在波浪环境中的应力作出公正的估计的困难。最近开发的分析技术已经记录了解释波浪引起的偏差的方法，允许使用通常部署的声学多普勒海流剖面仪（ADCP）的速度剖面直接观测沿海海洋应力。 这项工作建议使用这些方法来估计应力存在于一个超过10年的记录的速度剖面从玛莎葡萄园岛海岸天文台（MVCO）。 估计的应力将被利用，沿着与速度，水文，和风观测，以检查如何内架过程相互作用，以确定跨架交换由于沿架风，跨架风，和表面重力波和相关的动量转移的变化，由于这些过程的跨架交换的变化。 这些估计值将与在简单的一维和二维或复杂的三维数值模型模拟中使用常见湍流闭合模型对类似强迫条件的预测值进行比较。智力优势：湍流应力剖面的原位观测，传统上是动量方程中最难接近的项，是我们解释和预测沿海海洋动力学能力的核心。 使用长期数据集，这项工作将分离风或波浪强迫对雷诺应力的增量效应，检查跨大陆架环流对应力的依赖性。 将这些观测结果与数值模型的预测进行比较，将为评估闭合方法提供一个强大的新工具，从而能够更准确地预测在无法获得此类测量结果的情况下，引起压力的过程如何相互作用以驱动循环。 分析的主要数据产品，从MVCO的长期速度数据集估计的应力分布图，将被存档并在天文台的网站上提供，因此可作为社区数据产品用于未来的研究。更广泛的影响：控制水团和营养物跨大陆架交换的机制控制着沿海海洋的生产力以及浮游幼虫和污染物的扩散或滞留。 额外的知识湍流应力和它们的使用在评估模型参数化提供，潜在的，更精确的了解的动态的内架和跨架交换，然后以前已经可能，允许交换依赖的过程进行研究和建模，提高精度。 结果将通过教学和正在进行的推广计划直接传播到课堂。