Internal Tide Studies at the Hawaiian Ridge

夏威夷海脊的内潮研究

• 批准号: 0425347
• 负责人: Mark Merrifield
• 金额: $ 49.07万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-08-01 至 2008-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0425347&HistoricalAwards=false
• 关键词: Internal; Tide; Studies; Hawaiian; Ridge

0425347Intellectual merit: The pathways of energy transfer from the basin-scale surface tidal motions to the smallest turbulent mixing scales are not understood well. An important intermediate step is the scattering of the surface tide into internal tides at mid-ocean topography, such as seamounts, submerged ridges, and islands, which is a sink for barotropic tidal energy. Models show internal tides emanating from these generation regions with both beam structure, where energy density is localized along internal tidal characteristics, and low-mode structure. The high-mode components of the internal tide are believed to dissipate near the generation site and may be important for local mixing, while the low-mode internal tides propagate away from their source regions with decay scales on the order of 1000 km in observations and models. Our ability to predict this process depends on well-conceived models that are validated against field observations. The largest and most comprehensive tidal conversion study has been the Hawaii Ocean Mixing Experiment (HOME), focusing on tidal scattering at the ridge, seamount, and island topography making up the Hawaiian Ridge. The modeling component of this study has proven to be highly successful. The model simulations of internal tide generation and radiation compares favorably to observed currents, displacements, energy densities, energy fluxes, and dissipation. The continuation of the HOME tidal modeling effort is based on the Princeton Ocean Model. The goals of this project are to 1) finalize the tidal energy budget for the entire ridge, 2) examine non-hydrostatic features observed over the ridge crest, 3) assess the model turbulent closure scheme versus direct microstructure and finestructure measurements, 4) determine the amount of deep mixing occurring along the ridge flanks associated with internal tide beams, and 5) assess the sensitivity of the internal tide to changes in the background stratification and circulation. HOME provides an ideal test site to expand our understanding of the tidal scattering process, to assess current modeling approaches, and to develop new tools based on the field results. Broader impacts: Ultimately this activity can lead to improved parameterizations of tidal dissipation and mixing to be used in larger scale circulation and climate models, as well as in regional models for seamount and ridge environments. An undergraduate and two graduate student will participate in this project, with the goal of achieving a senior thesis and PhD dissertations. The project will be highlighted during the annual public open house at the University of Hawaii, an outreach activity sponsored by the School of Ocean Earth Science and Technology. The Bishop Museum in Honolulu, Hawaii will be contacted to discuss a possible display based on the results of this study.

0425347智力上的优点：从盆地尺度的表面潮汐运动到最小的湍流混合尺度的能量转移的路径还没有被很好地理解。一个重要的中间步骤是在海洋中部地形，如海山、淹没的海脊和岛屿，将表层潮汐散射成内部潮汐，这是正压潮汐能量的汇。模型显示了从这些发源区发出的内潮既有波束结构，能量密度沿内潮汐特征局部化，也有低模结构。内潮的高模分量被认为在产生点附近消散，对局部混合可能是重要的，而低模内潮在观测和模式中以1000公里量级的衰减尺度远离其源区。我们预测这一过程的能力依赖于构思良好的模型，这些模型经过现场观测验证。最大和最全面的潮汐转换研究是夏威夷海洋混合实验(HOME)，重点是组成夏威夷海脊的海脊、海山和岛屿地形的潮汐散射。这项研究的建模部分被证明是非常成功的。内潮产生和辐射的模式模拟与观测到的电流、位移、能量密度、能量通量和耗散相比较有利。家庭潮汐模型的继续工作是基于普林斯顿海洋模型。该项目的目标是：1)最后确定整个海脊的潮汐能量收支，2)检查在海脊上观察到的非静力特征，3)评估模型湍流闭合方案与直接微观结构和精细结构测量的对比，4)确定与内部潮汐有关的海脊侧翼发生的深层混合量，以及5)评估内潮对背景层结和环流变化的敏感性。HOME提供了一个理想的试验场，以扩大我们对潮汐散射过程的理解，评估现有的模拟方法，并根据现场结果开发新的工具。更广泛的影响：归根结底，这项活动可以改进潮汐耗散和混合的参数化，用于更大规模的环流和气候模型，以及用于海山和海脊环境的区域模型。一名本科生和两名研究生将参与这个项目，目标是获得高级学位论文和博士学位论文。该项目将在夏威夷大学一年一度的公众开放日期间得到强调，这是由海洋地球科学与技术学院赞助的一项外联活动。将联系夏威夷火奴鲁鲁的主教博物馆，根据这项研究的结果讨论可能的展示。