Collaborative Research: Tasmanian Tidal Dissipation Experiment (T-TIDE)

合作研究：塔斯马尼亚潮汐消散实验（T-TIDE）

• 批准号: 1129782
• 负责人: Jonathan Nash
• 金额: $ 67.94万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1129782&HistoricalAwards=false
• 关键词: Collaborative; Research; Tasmanian; Tidal; Dissipation

Intellectual MeritTidal mixing of the deep ocean does not necessarily occur where energy is lost from the barotropic tide, but rather where the low-mode baroclinic tide dissipates, perhaps thousands of kilometers away. Ocean general circulation models are sensitive to the magnitude and geography of deep mixing, but very few observations of this process exist. Understanding the location and mechanisms of tidal dissipation is necessary for their continued improvement. The Tasmanian Tidal Dissipation Experiment?s (T-TIDE) hypothesis is that significant tidal dissipation takes place where propagating low-mode internal tides impinge on steep continental slopes. Slope geometry affects wave reflection, transmission, scattering, and breaking, which in turn determine the spatial distribution of mixing. Important breaking mechanisms may include lee effects at small-scale bathymetry and nonlinear bore formation near critical slopes. We propose a coordinated observational/modeling effort to understand the physics geometry, and magnitude of dissipation and mixing. The goals are to 1) identify where mixing occurs on the continental slope, 2) determine the dominant dissipative processes, 3) assess the amount of energy transmitted onto the shelf and reflected back into the deep sea to be dissipated elsewhere, and 4) generalize these results as a parameterization of topographic scattering and dissipation in numerical models, which ideally depends on the topography, stratification, and the barotropic and/or low-mode baroclinic tides. The three main components to the experimental plan are 1) intensive 2D and 3D modeling before and after the fieldwork to plan and contextualize the measurements; 2) a glider based Scout Experiment to identify dynamic processes, evaluate models, and finalize mooring sites; and 3) a comprehensive Process Experiment using ships, gliders, and moorings with the time and space resolution to address T-TIDEs hypothesis and achieve its goals. An array of profiling and fixed-sensor moorings will be combined with gliders acting as virtual moorings. Tidally-resolving or higher-frequency observations will measure internal wave motions, energy fluxes, and dissipation and mixing either directly or via finescale parameterizations. An altimetric analysis of internal-tide sea surface height will assess mesoscale refraction of the incident internal tide along with Australian gliders, which will monitor hydrography and internal tidal displacements in the Tasman Sea. Broader ImpactsThe proposed work will provide global insights on the dissipation of tidal energy. Specifically, inclusion of tidal dissipation on continental slopes may be an important component of the next generation of mixing parameterizations in climate models. Graduate students will be trained as part of the experiment. In addition to its scientific import, T-TIDE will sponsor and participate in two training seminars with high school science teachers who are charged with delivering the earth science program in San Diego Unified School District. This effort will be performed in conjunction with the Birch Aquarium at Scripps. Finally, an essential element of the project is the development of strong collaboration and resource sharing with Australian and Canadian scientists.

深海的智力Merittidal混合不一定发生在偏压潮汐中损失的能量的情况下，而是在低模式的Barocloclinic潮汐消散的地方，也许是数千公里。 海洋一般循环模型对深层混合的大小和地理敏感，但是对此过程的观察很少。 了解潮汐耗散的位置和机制对于它们的持续改进是必要的。 塔斯马尼亚潮汐耗散实验？S（t-tide）假设是否发生了明显的潮汐耗散，在陡峭的大陆斜坡上散发出低模式的内部潮汐。 斜率几何形状会影响波形反射，透射，散射和破裂，这又决定了混合的空间分布。 重要的破坏机制可能包括在临界斜率附近的小规模测深的李效应和非线性孔形成。 我们提出了一个协调的观察/建模工作，以了解物理几何形状以及耗散和混合的幅度。 The goals are to 1) identify where mixing occurs on the continental slope, 2) determine the dominant dissipative processes, 3) assess the amount of energy transmitted onto the shelf and reflected back into the deep sea to be dissipated elsewhere, and 4) generalize these results as a parameterization of topographic scattering and dissipation in numerical models, which ideally depends on the topography, stratification, and the barotropic and/or low-mode斜压潮。 实验计划的三个主要组成部分是1）在现场工作之前和之后进行密集的2D和3D建模，以计划和背景测量； 2）基于滑翔机的侦察实验，以识别动态过程，评估模型并确定系泊设备； 3）使用船舶，滑翔机和系泊设备进行全面的过程实验，并分辨出时间和空间，以解决T-tides假设并实现其目标。 一系列的分析和固定传感器系泊将与充当虚拟系泊的滑翔机结合使用。 潮汐分辨或更高频观测将测量内部波动，能量通量以及耗散和通过罚款参数化进行耗散和混合。 内部潮汐海面高度的高度分析将评估入射内潮​​的中尺度折射以及澳大利亚滑翔机，澳大利亚滑翔机将监测塔斯曼海的水文图和内部潮汐位移。 更广泛的影响拟议的工作将提供有关潮汐能量消散的全球见解。具体而言，将潮汐耗散纳入大陆斜率可能是在气候模型中下一代混合参数化的重要组成部分。 研究生将作为实验的一部分进行培训。 除科​​学进口外，T-Tide还将赞助并与高中科学教师一起参加两个培训研讨会，这些教师负责在圣地亚哥统一学区提供地球科学计划。 这项工作将与Scripps的桦木水族馆一起进行。最后，该项目的基本要素是与澳大利亚和加拿大科学家的强大合作和资源共享的发展。