Collaborative Research: Mesoscale Drivers of Oxygen in the Tropical Pacific

合作研究：热带太平洋氧气的中尺度驱动因素

• 批准号: 1948718
• 负责人: Matthew Long
• 金额: $ 12.99万
• 依托单位: University Corporation For Atmospheric Res
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-03-15 至 2025-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1948718&HistoricalAwards=false
• 关键词: Collaborative; Research; Mesoscale; Drivers; Oxygen

The tropical Pacific Ocean is home to rich marine biodiversity and abundant fisheries. It is also the most oxygen-deficient basin in the world, hosting the world’s largest oxygen minimum zones (OMZs). The northern and southern tropical Pacific OMZs are separated by oxygen-rich waters along the equator that provide important habitable space for open ocean fisheries whose feeding behavior is limited by the depth at which oxygen levels decrease below uninhabitable thresholds. Characterizing the processes that control the depth of this low oxygen threshold is important to understanding ecosystem dynamics and to predicting and managing fisheries in this region. The primary goal for this project is to understand the role of regional physical processes in setting the 3-dimensional structure of oxygen in the equatorial Pacific and its changes on seasonal and interannual time scales. The investigators will use a combination of computer models and existing observations to describe the role that regional circulation patterns play in maintaining the volume and oxygen content of the Pacific OMZs. These include global models of ocean circulation and biological and chemical processes controlling the OMZ, as well as models that focus on regional scale features of ocean circulation (such as eddies) and that are informed by observations. The oceanic oxygen cycle integrates physical, biological, and chemical phenomena, making it an ideal curriculum topic for applying Next Generation Science Standards (NGSS) into K-12 classrooms. In this project, the investigators will work closely with NGSS early implementers from the local school districts to introduce this project’s research questions, knowledge, and relevant data and visualization tools into the lesson plans, exposing students and teachers directly to the scientific process. A major knowledge gap concerns the role of the equatorial current system (ECS) and tropical instability vortices (TIVs) in ventilating the OMZs, and the extent to which oxygen supply by these ventilation pathways is compensated by their effects on nutrient transport, productivity, and respiration rates, motivating the following questions: 1. How does the equatorial current system and its interaction with mesoscale eddies modulate the boundaries and ventilation of the OMZs? 2. What governs the seasonal to interannual variability of OMZ ventilation in this region? 3. Through what physical and biogeochemical mechanisms do TIVs influence equatorial Pacific oxygen? A central hypothesis for this proposal is that lateral transport by the Equatorial Undercurrent and TIV-mediated fluxes play a dominant role in setting the mean oxygen structure and variability of the upper equatorial Pacific. These questions will be examined using a hierarchy of models of various configurations, including an eddy resolving and coarse global model, an eddy resolving data-assimilating regional model of the tropical Pacific, and Lagrangian analysis. The work is expected to i) elucidate the mechanisms coupling oxygen to ocean circulation and climate variability in the tropical Pacific, ii) inform drivers of OMZ biases in models, and iii) guide observing needs including the on-going Tropical Pacific Observing System (TPOS 2020) efforts and future deployments of biogeochemical (BGC) Argo floats in this region.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.

热带太平洋拥有丰富的海洋生物多样性和丰富的渔业资源，也是世界上最缺氧的盆地，拥有世界上最大的氧气最低区（OMZ）。赤道沿岸富饶的水域为公海渔业提供了重要的宜居空间，其摄食行为受到氧气水平降至不适宜居住阈值的深度的限制，表征控制这种低氧阈值深度的过程对于了解生态系统动态非常重要。该项目的主要目标是了解区域物理过程在确定赤道太平洋氧气的三维结构中的作用及其在季节和年际时间尺度上的变化。结合计算机模型和现有观测来描述区域环流模式在维持太平洋 OMZ 的体积和氧气含量方面所发挥的作用，其中包括海洋环流和控制 OMZ 的生物和化学过程的全球模型，以及控制 OMZ 的模型。注重区域性海洋环流（如涡流）的尺度特征，并通过观测了解海洋氧循环整合了物理、生物和化学现象，使其成为将下一代科学标准 (NGSS) 应用到 K-12 课堂的理想课程主题。在该项目中，研究人员将与当地学区的NGSS早期实施者密切合作，将该项目的研究问题、知识以及相关数据和可视化工具引入到课程计划中，让学生和教师直接接触科学过程。差距涉及赤道洋流系统 (ECS) 和热带不稳定涡旋 (TIV) 在 OMZ 通风中的作用，以及这些通风路径的氧气供应在多大程度上通过它们对营养物运输、生产力和呼吸速率的影响得到补偿，从而激发了以下方面的作用：问题： 1. 赤道洋流系统及其与中尺度涡流的相互作用如何调节 OMZ 的边界和通风？ 2. 是什么控制着赤道洋流的季节到年际变化？该地区的 OMZ 通风？ 3. TIV 通过什么物理和生物地球化学机制影响赤道太平洋的氧气？该提议的一个中心假设是赤道潜流和 TIV 介导的通量的横向输送在设定平均氧气结构中发挥主导作用。这些问题将使用各种配置的模型层次结构进行研究，包括涡旋解析和粗略全球模型、涡旋解析数据同化区域模型。这项工作预计将 i) 阐明热带太平洋中氧气与海洋环流和气候变化的耦合机制，ii) 告知模型中 OMZ 偏差的驱动因素，以及 iii) 指导观测需求，包括实时观测。热带太平洋观测系统 (TPOS 2020) 的努力以及生物地球化学 (BGC) Argo 浮标在该地区的未来部署。该奖项反映了 NSF 的法定使命，并通过评估被认为值得支持利用基金会的智力优势和更广泛的影响审查标准。