Collaborative Research: Global eddy-driven transport estimated from in situ Lagrangian observations

合作研究：根据原位拉格朗日观测估计全球涡流驱动的输运

• 批准号: 2049576
• 负责人: Harper Simmons
• 金额: $ 4.85万
• 依托单位: University of Alaska Fairbanks Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-15 至 2023-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2049576&HistoricalAwards=false
• 关键词: Collaborative; Research; Global; eddy; driven

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).This project will examine fluid transport by long-lived coherent mesoscale eddies in the global ocean, including volumes within their coherent cores, transiently trapped fluids in eddy peripheries, and stirring effects in the ambient watermasses due to eddy influence therein. The project would rely on a novel eddy-identifying analysis technique (developed in prior work by the PIs) applied to in-situ measurements from global surface drifter dataset and the historical set of acoustically-tracked subsurface floats. This is a departure from the usual approach of eddy detection in gridded satellite products, relying instead on the adaptation of signal processing techniques to float trajectory data. Prior studies based on such gridded products significantly underestimate numbers of eddies, and overestimate eddy sizes and transport of water trapped within them. Data analysis will be supplemented by theoretical idealized and realistic numerical modeling. This work will address what observed ubiquitous coherent eddies actually accomplish in terms of their effect on the large-scale flow. This is a question of societal importance because of its relevance for the development of accurate subgrid-scale parameterizations for general circulation models. The project will advance the boundaries of the viable use of Lagrangian data, and thus provide new tools for eddy examination to the community. The project will support and inform free online courses in fundamental and advanced oceanographic data analysis, so that that these state-of-the-art methodologies will be broadly accessible to the next generation of researchers. The project supports an early career latino scientist, who will develop an undergraduate-level teaching module related to this project.This project will produce a definitive study on the role of coherent eddies in driving fluid transport, taking significant eddy detections from in situ Lagrangian observations as the starting point. The detection method, called vortex signal extraction, recovers time-varying oscillatory signal components from Lagrangian trajectories, without a requirement for the oscillations to be strictly periodic. Available data include approximately 24,000 global surface drifter trajectories plus another 3,000 subsurface trajectories from an historical set of eddy-resolving floats, both NOAA datasets. Data analysis will be complemented by idealized and ultra-high-resolution realistic modeling. These components will be used to explore the subtleties of observing the eddy field from the Lagrangian perspective, to examine the theoretical properties of the eddy detection methods, and to investigate the dynamics of the transport processes of interest. The project will proceed in three branches: (i) dynamics of direct and indirect eddy-driven transport, (ii) the vortex observability problem, and (iii) global estimates. Anticipated products will be new global estimates of coherent eddy properties, populations, and boundaries through statistical modeling informed by an improved understanding of the physics of long-term and transitory trapping. The project will further provide a calibration process by which remotely-sensed features can be more accurately mapped onto fluid structures, and a hydrographic analysis will convert areal transport estimates into mass transports.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.

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).This project will examine fluid transport by long-lived coherent mesoscale eddies in the global ocean, including volumes within their coherent cores, transiently trapped fluids in eddy peripheries, and stirring effects in the ambient watermasses due to eddy influence therein.该项目将依靠一种新型的涡流识别分析技术（PIS在先前的工作中开发），该技术应用于全球表面漂流者数据集的原位测量以及听觉跟踪的地下浮子的历史集。这与网格卫星产品中涡流检测的通常方法背道而驰，而是依靠信号处理技术的适应来浮动轨迹数据。先前基于此类网格产品的研究显着低估了涡流的数量，并且高估了被困在其中的水的大小和运输。数据分析将通过理论理想化和现实的数值建模来补充。这项工作将解决观察到的无处不在的相干涡流实际上在其对大规模流动的影响方面所实现的目标。这是一个社会重要性的问题，因为它与开发一般循环模型的准确亚网格尺度参数化相关。该项目将推动可行使用拉格朗日数据的界限，从而为社区提供新工具。该项目将在基本和先进的海洋学数据分析中支持并为免费的在线课程提供信息，以便下一代研究人员可以广泛访问这些最先进的方法。该项目支持一位早期的职业拉丁裔科学家，他将开发与该项目相关的本科教学模块。该项目将对相干涡流在驱动流体运输方面的作用进行确定的研究，从而从现场Lagrangian观察中进行大量涡流检测。检测方法称为涡流信号提取，从拉格朗日轨迹中恢复了时变的振荡信号成分，而无需严格周期性振荡。可用的数据包括大约24,000个全球表面漂移轨迹，再加上另外3,000个地下轨迹，其中包括一组涡流的浮子，均为NOAA数据集。数据分析将由理想化和超高分辨率的现实建模补充。这些成分将用于探索从拉格朗日角度观察涡流的微妙之处，以检查涡流检测方法的理论特性，并研究感兴趣的传输过程的动力学。该项目将分为三个分支：（i）直接和间接涡流传输的动态，（ii）涡流可观察性问题以及（iii）全球估计。预期的产品将是通过对长期和短暂陷阱物理学的了解，通过统计建模来了解一致的涡流，种群和边界的新全球估计。该项目将进一步提供校准过程，可以通过该过程更准确地映射到流体结构上，水文分析将把面积的传输估计转换为大规模运输。这奖反映了NSF的法定任务，并被认为是值得通过基金会的知识分子和更广泛影响的审查审查标准来通过评估来通过评估来获得支持的。