Collaborative Research: Next-generation Global Altimetric Maps of Internal Tide Energy Flux and Dissipation

合作研究：下一代全球内潮汐能量通量和耗散高度图

• 批准号: 1129129
• 负责人: Zhongxiang Zhao
• 金额: $ 58.62万
• 依托单位: University of Washington
• 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: 2011-09-15 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1129129&HistoricalAwards=false
• 关键词: Collaborative; Research; Next; generation; Global

Intellectual Merit:Breaking internal tides are known to be a major driver of deep-ocean diapycnal mixing. However, much of the energy input into them is in the first few modes, which can propagate 1000's of kilometers before breaking. As a result, little is known about where and how they break, in spite of the known sensitivity of global circulation models to the geography of mixing. Therefore, this study will construct a global map of low-mode internal tide energy flux and dissipation by application of state-of-the-art techniques to a combination of satellite altimetry, moorings, and a numerical model. The approach captures both the non-uniform barotropic-to-baroclinic tide conversion near rough topography as well as patchiness due to the non-uniform dissipation of low-mode internal tides.The global coverage of satellite altimeters makes them the only practical observational tool available for the task. However the poor spatial resolution of any single satellite, and the inability of altimetry to detect temporally incoherent signals, have hampered the interpretation of past altimetric estimates of low-mode internal tide energy and energy flux. This study addresses these shortcomings in order to produce the needed global maps:(1) To address the low-resolution problem, the team will expand on their previous work (in which they used the T/P-Jason tandem mission) by combining multiple satellite altimetric data from T/P- Jason, T/P-Jason tandem, GFO, and ERS. The multi-satellite technique was recently demonstrated in the North Pacific, and showed that spatial resolution is improved to the point where the altimetric estimates agree with high-resolution numerical models.(2) To understand the loss of coherence of internal tide propagating in an ever-changing ocean, the PIs will analyze a new high-resolution global simulation that includes a realistic internal tide field as well as realistic meso- and large-scale ocean circulations. The model estimate of how the non- uniform moving ocean makes internal tide incoherent will be validated by the analysis of several long moored time series collected around the globe.With these improvements, the techniques should now be up to the task of mapping the low-mode internal tide's energy flux and dissipation on the globe. In doing so, this project will lead to a better understanding of the processes that affect the propagation and dissipation of internal tide on a global scale.Broader Impacts:The primary broader impact of this work will be an improved understanding and a parameterization of the magnitude and geography of dissipation, of known importance to general circulation models. In addition, the team will provide maps of altimetrically-observed internal tide quantities to all researchers as well as the public via a website and/or direct communication with the PI's. In addition to being of great use in planning experiments, such maps will be of relevance for a variety of physical and biogeochemical studies. The maps and the model simulations will be used in community outreach programs such as APL's K-12 volunteer list and Seattle's Pacific Science Center. The study will also educate three undergraduate students as part of the Washington Space Grant program, a joint program between Washington State and NASA seeking to encourage students at the University of Washington to pursue science careers.

知识分子的优点：众所周知，破裂的内部潮汐是深度海洋混合的主要驱动力。但是，其中的大部分能量输入都是在前几种模式中，在破裂之前可以传播1000千米。结果，尽管全球循环模型对混合地理的敏感性具有已知的敏感性，但对它们的破裂位置和方式知之甚少。因此，这项研究将通过将最先进的技术应用于卫星高度测定，系泊和数值模型的组合来构建一个低模式内部潮汐能通量和耗散的全球图。该方法捕获了不均匀的正压到 - 横向潮汐的潮汐转换，以及由于低模式内部潮汐的非均匀耗散而引起的斑块。卫星高度计的全球覆盖范围使它们成为唯一可用于任务的实际观察工具。然而，任何单个卫星的空间分辨率差，以及高度测定的无法检测到时间不连贯的信号的能力，阻碍了对低模式内部潮汐能量和能量通量的过去高度估计值的解释。这项研究解决了这些缺点，以生成所需的全球图：（1）为解决低分辨率问题，团队将通过结合来自T/P-Jason，T/P-Jason Tandem，GFO，GFO和ERS的多个卫星高度图来扩展其先前的工作（其中他们使用T/P-Jason串联任务）。 The multi-satellite technique was recently demonstrated in the North Pacific, and showed that spatial resolution is improved to the point where the altimetric estimates agree with high-resolution numerical models.(2) To understand the loss of coherence of internal tide propagating in an ever-changing ocean, the PIs will analyze a new high-resolution global simulation that includes a realistic internal tide field as well as realistic meso- and large-scale ocean循环。通过分析在全球范围内收集的几个长期系泊的时间序列的分析，将验证非统一移动海洋如何使内部潮流的模型估计。随着这些改进，这些技术现在应符合绘制低模式内部潮汐的能量范围和全球消散的任务。为此，该项目将更好地理解影响全球范围内部潮汐传播和耗散的过程。BROADER的影响：这项工作的主要更广泛的影响将是对耗散大小和地理位置的参数化，对一般循环模型的重要性。此外，该团队将通过网站和/或与PI的直接通信为所有研究人员以及公众提供高度观察到的内部潮汐数量的地图。除了在计划实验中有很大的用途外，此类地图还与各种物理和生物地球化学研究有关。地图和模型模拟将用于社区外展计划，例如APL的K-12志愿者名单和西雅图的太平洋科学中心。这项研究还将教育三名本科生作为华盛顿州立大学和NASA之间的联合计划的一部分，该计划寻求鼓励华盛顿大学的学生从事科学职业。