A Global Distributed Observing Program for Shear, Energy Flux, and Mixing by Internal Waves

全球分布式剪切、能量通量和内波混合观测计划

• 批准号: 2232796
• 负责人: James Girton
• 金额: $ 422.46万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-01-01 至 2025-12-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2232796&HistoricalAwards=false
• 关键词: Global; Distributed; Observing; Program; Shear

Mixing rates in the ocean of the future will be determined to a large extent by the distribution of internal waves. Changes in the forcing of these waves by winds and tides, and modifications of the currents and density stratification that modulate internal wave propagation, evolution, and eventual dissipation into turbulence, are likely to be simulated with some skill by numerical coupled climate models. But the waves themselves and their impacts on the climate system through diffusive transport of heat, chemicals, and other tracers are a more difficult challenge. This project starts a global sampling program for internal waves using profiling floats- measuring temperature, salinity, velocity, and turbulence—that will yield new insights into internal wave regimes and parameterizations, and that will provide direct and derived data products tailored for use by modeling groups for comparison and validation. Velocity profiling floats paired with microstructure sensors are an ideal, proven platform for globally- distributed measurements of internal waves and their mixing impacts. Much of the energy in the internal wave field enters at large vertical scales (particularly true for internal tides), yet energy dissipation happens through shear and strain at small scales. Velocity profiles resolve this full range of vertical scales, and bursts of profiles provide the direction and magnitude of energy flux in dominant frequency bands. Deployment of profiling floats in all dynamical regimes around the globe will provide data sets resolving both the waves and their impact on mixing. This project will also create data practices for sharing direct and derived products (metrics) with numerical modelers. The improved insight into internal wave forcing, propagation, and dissipation will lead to improved forecasts of processes that are influenced by internal wave mixing and transport. These include centennial-scale forecasts of heat and carbon penetration into the deep ocean, seasonal forecasts of coastal ecosystem nutrient supply through upwelling and shelf-slope exchange, and decadal and longer evolution of upper-ocean stratification and the meridional overturning circulation. Once developed, the sampling methodologies and data tools can be applied to future velocity and turbulence profiling float data sets. In addition, this work will permit maintenance of instrument development and seagoing field work expertise and will support ongoing education and outreach efforts.Principal activities Include (1) deployment of 50 velocity and microstructure profiling floats from 6 cruises of opportunity, over 3 years, in diverse locations around the globe spanning the range of the dominant parameters that determine the internal wave environment. (2) derivation of internal wave products for use in (a) estimating internal wave impacts on mixing and the kinetic energy budget of the ocean, (b) projecting surface signatures of internal waves seen by satellite sensors into subsurface vertical structure and frequency bands, (c) validation of internal wave resolving models, and (d) internal wave resolving data assimilation. (3) Development of operational data pathways from velocity and microstructure profile collection to operational modeling and archiving centers. (4) Using the merged and augmented profiling float measurement database to assess the relative roles of wind, tides, topography, and mesoscale variability in generating and dissipating the energy seen in the oceanic internal wave field.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

未来海洋中的混合速率将通过内波的分布在很大程度上确定。通过风和潮汐对这些波的强迫变化，以及将内波传播，进化和最终耗散变为湍流的电流和密度分层的修改，可能会通过数值耦合攀岩模型模拟某些技能。但是，通过不同的热量，化学物质和其他示踪剂的运输，海浪本身及其对气候系统的影响是一个更加困难的挑战。该项目启动了使用分析浮子的全局抽样程序，用于内部波动，测量温度，盐度，速度和湍流，这将产生对内部波浪制度和参数的新见解，并将提供用于对比较和验证的建模组来量身定制的直接和派生数据产品。与微结构传感器配对的速度分析浮子是全球分布式内波及其混合撞击的理想平台。内波场中的许多能量都以较大的垂直尺度（部分为内部潮汐）进入，但是能量耗散是通过剪切和应变在小尺度上发生的。速度曲线解决了这一完整的垂直尺度，并且轮廓爆发提供了优势频带中能量通量的方向和大小。在全球所有动态制度中，该项目的分析浮子部署还将创建与数值建模器共享直接和衍生产品（指标）的数据实践。对内波强迫，繁殖和耗散的洞察力的改善将导致受内波混合和运输影响的外国过程改善。其中包括通过上升和架子 - 斜坡交换的沿海生态系统养分供应的一百周年尺度森林，沿海生态系统营养供应的季节性森林，以及上海上层的十年且较长的进化以及子午线翻转循环。一旦开发，采样方法和数据工具就可以应用于将来的速度和湍流分析浮点数据集。此外，这项工作将允许维持仪器开发和海上现场工作专业知识，并将支持正在进行的教育和外展工作。（1）包括3年机会的6年巡游中的50个速度和微观结构谱图在全球范围内的潜水员范围内，从6年的机会巡游中浮动，这些速度跨越了内部波浪环境的主要范围。 （2）用于（a）估计内波对混合的影响和海洋动能预算的影响，（b）卫星传感器看到的内波的表面特征的影响（a）用于（a）内波的影响，（c）验证内部波溶解模型的验证，以及（d）内波的验证（d）内波溶解数据。 （3）开发从速度和微观结构概况收集到操作建模和归档中心的操作数据途径。 （4）使用合并和增强的谱图浮点测量数据库来评估风，潮汐，地形和中尺度的相对作用在产生和消散海洋内部波浪领域中所见能量方面的可变性。该奖项反映了NSF的法规任务，并通过使用基金会的知识优点和广泛的评估来评估，并通过评估诚实地进行了评估。