Collaborative Research: Hydraulic Control and Mixing of the Deep Ocean Flow through the Samoan Passage

合作研究：萨摩亚海峡深海流的水力控制和混合

• 批准号: 1657870
• 负责人: Lawrence Pratt
• 金额: $ 24.79万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-03-15 至 2020-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1657870&HistoricalAwards=false
• 关键词: Collaborative; Research; Hydraulic; Control; Mixing

The large-scale circulation of the ocean also known as the Meridional Overturning Circulation (MOC) comprises a series of shallow and deep water currents that transport mass, heat, carbon, and nutrients around the globe. The Samoan Passage, which carries the majority of the transport in its deep northward branch, is an important element of the Pacific Ocean circulation system. Recent observations supported by a previously funded NSF project have identified a previously unknown split of the flow between a deeper eastern channel and multiple shallower, western pathways within the Samoan Passage complex. Additional changes such as a warming and weakening of the flow through the passage have also been observed over the past twenty years, which supports the need for long-term observations. This project will examine the dynamics of the flow through the Samoan Passage in detail using a combination of observations, theory and numerical models. Currently, there are no deep ocean monitoring system deployed in the Pacific MOC and this project has the potential to aid in the development of an observing system that can complement the one currently deployed in the Atlantic. Climate models predict a weakening of the global overturning circulation, which could be confirmed or refuted with these observing systems. The knowledge gained from the proposed work can likely be applied to similar deep passages and fracture zones around the world. Two early career scientists, summer undergraduates, a graduate student and a post-doctoral researcher will gain valuable training in modern methods used in oceanography through this project. Diverse outreach activities are planned to engage the public with the results and knowledge gained from this project through collaborations with a modern dance company, and the Birch Aquarium and a high school in San Diego.Extensive measurements collected under previous NSF funding, including a combination of moored time series and deep towed measurements will be used to study hydraulic effects on the flow in the Samoan Passage. Strong turbulent mixing was observed as the flow passes through and over various constrictions and sills, thereby substantially altering its water mass characteristics. The recent measurements indicate hydraulic criticality of the flow through the Samoan Passage, at least at one major sill. The three specific objectives of this project include: investigating the influence of hydraulic processes on mixing and friction at various sills, studying hydraulic criticality and implications for transport and partition of the flow through and around the Samoan Passage, and informing an efficient monitoring strategy for the flow through the Samoan Passage. As a result of this project, hydraulic theory will be improved and observationally validated, making it applicable to dense overflows in other passages and to the flow in the multitude of fracture zones that are believed to be important drivers for abyssal upwelling.

海洋的大规模循环也称为子午倾覆循环（MOC），包括一系列浅水和深水电流，这些水流在全球范围内运输质量，热，碳和营养素。萨摩亚通道（Samoan Passage）是太平洋循环系统的重要元素。由先前资助的NSF项目支持的最新观察结果已经确定了萨摩亚通道复合体内的较深的东部通道和多个较浅的西方途径之间的流动群。在过去的二十年中，还观察到了其他变化，例如通过通道的流动和弱化的流动，这支持了长期观察的需求。 该项目将使用观测值，理论和数值模型的组合详细研究通过萨摩亚通道的流动动力学。目前，太平洋MOC中没有部署的深海洋监测系统，该项目有可能帮助开发一种观察系统，该系统可以补充目前在大西洋地区部署的系统。气候模型预测全球倾覆循环的削弱，可以通过这些观察系统来确认或驳斥。从拟议的工作中获得的知识可能应用于世界各地的类似深层通道和骨折区域。两名早期职业科学家，夏季大学生，一名研究生和一名博士后研究人员将通过该项目获得海洋学中使用的现代方法的宝贵培训。 计划通过与现代舞蹈公司的合作以及桦木水族馆和圣地亚哥的一所高中获得该项目获得的结果和知识，以吸引公众。当流动通过并在各种收缩和窗台上传递时，观察到了强烈的湍流混合，从而实质上改变了其水量特征。最近的测量表明，至少在一个主要的门槛上，流过萨摩亚通道的流动性临界性。该项目的三个特定目标包括：研究液压过程对各种窗台上混合和摩擦的影响，研究液压临界性以及对通过萨摩亚通道和周围流动的运输和分配的含义，并为通过萨摩亚通道流过的有效监控策略提供了有效的监视策略。该项目的结果是，液压理论将得到改善并在观察上进行验证，使其适用于其他段落中的密集溢出，以及在许多断裂区域中的流动，这些裂缝区域被认为是深处上升的重要驱动因素。

项目成果

Persistent Turbulence in the Samoan Passage

• DOI: 10.1175/jpo-d-19-0116.1
• 发表时间: 2019-12
• 期刊: Journal of Physical Oceanography
• 影响因子: 3.5
• 作者: J. Cusack;Gunnar Voet;M. Alford;J. Girton;G. Carter;L. Pratt;Kelly A. Pearson-Potts;Shuwen Tan

Pacific Abyssal Transport and Mixing: Through the Samoan Passage versus around the Manihiki Plateau

• DOI: 10.1175/jpo-d-18-0124.1
• 发表时间: 2019-06
• 期刊: Journal of Physical Oceanography
• 影响因子: 3.5
• 作者: L. Pratt;Gunnar Voet;A. Pacini;Shuwen Tan;M. Alford;G. Carter;J. Girton;D. Menemenlis

A Spatial Geography of Abyssal Turbulent Mixing in the Samoan Passage

萨摩亚海峡深海湍流混合的空间地理

• DOI: 10.5670/oceanog.2019.425
• 发表时间: 2019
• 期刊: Oceanography
• 影响因子: 2.8
• 作者: Carter, Glenn;Voet, Gunnar;Alford, Matthew;Girton, James;Mickett, John;Klymak, Jody;Pratt, Larry;Pearson-Potts, Kelly;Cusack, Jesse;Tan, Shuwen
• 通讯作者: Tan, Shuwen

Flow-Topography Interactions in the Samoan Passage

萨摩亚航道的水流-地形相互作用

• DOI: 10.5670/oceanog.2019.424
• 发表时间: 2019
• 期刊: Oceanography
• 影响因子: 2.8
• 作者: Girton, James;Mickett, John;Zhao, ZhongXiang;Alford, Matthew;Voet, Gunnar;Cusack, Jesse;Carter, Glenn;Pearson-Potts, Kelly;Pratt, Larry;Tan, Shuwen
• 通讯作者: Tan, Shuwen