Collaborative research: Understanding the spatial and temporal variability of dissolved oxygen through a hierarchy of models.

合作研究：通过模型层次结构了解溶解氧的空间和时间变化。

• 批准号: 0851497
• 负责人: Takamitsu Ito
• 金额: $ 39.68万
• 依托单位: Colorado State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-04-01 至 2012-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0851497&HistoricalAwards=false
• 关键词: Collaborative; research; Understanding; spatial; temporal

Abstract In this project ocean modelers at The University of California at Los Angeles and Colorado State University will develop a new theoretical framework for understanding and predicting the responses of oceanic oxygen to wide range of climate variability. Recent observations of decadal oxygen changes of in the upper ocean, which now have been documented in every ocean basin, motivate several questions regarding the underlying mechanisms. How does dissolved oxygen respond to atmospheric forcing at different time scales? How do the temporal spectrum and spatial patterns relate to that of its driving forces, both physical and biological, and to the coupling between them? Modeling studies on long-term trends and basin-scale variability revealed that dissolved oxygen is highly sensitive to both physical and biological processes, and it has been suggested as a tracer of climate change in the oceans. However, mechanistic understanding of underlying causes are far from complete, and fuller elucidation of the large-scale modes of oxygen variability is therefore needed, particularly as new data is rapidly increasing. The research team hypothesizes that the physical and biological drivers of oxygen changes are modulated by the thermocline ventilation in the upper ocean, leading to enhanced large-scale, low frequency variability. The theory leads to novel hypotheses for explaining two recurring and general observations: that O2 changes are so prevalent at decadal time scales and are focused in waters occupying a common position in the water column, namely the base of the ventilated thermocline. They plan to evaluate these predictions using a hierarchy of models ranging from a one-dimensional isopycnal model to a state-of-the-art eddy-permitting global ocean model with ecosystem and biogeochemistry components. The work plan will involve comparison of patterns across a hierarchy of models, illuminating fundamental and non-model dependent dynamics of the oceanic oxygen cycle. This project culminates in the application of our theoretical and modeling approach to the Observing System Simulation Experiments (OSSEs) for the proposed global implementation of ARGO-O2 project to develop future observational strategies. This will be a major step toward building a set of tools for understanding the types of O2 variability found in the real world, and laying the groundwork for analyzing a wide range of observational and modeling data for this important tracer. Broader Impacts: The researchers anticipate that this work will shed light on hypoxia as an emerging problem in the ocean of strategic importance to fisheries managers and marine conservation efforts. Through the proposed OSSEs, this project will assist in the formulation of optimal observational strategies for the international efforts to develop the global array of O2 sensors on ARGO floats. The results are also expected to provide a mechanistic basis for estimating global scale losses of O2 from such irregular sampling networks, thus reducing a key uncertainty in the quantification of the partitioning of anthropogenic CO2 uptake between the land and the oceans. Finally, the project will provide for the training and support of two beginning graduate students, as well as outreach activities at Coloado Statue University on oceans and climate science for K-12 through graduate students and for the general public.

摘要 在该项目中，加州大学洛杉矶分校和科罗拉多州立大学的海洋建模人员将开发一个新的理论框架，用于理解和预测海洋氧气对大范围气候变化的响应。最近对上层海洋十年间氧气变化的观察（现已在每个海洋盆地都有记录）引发了有关潜在机制的几个问题。溶解氧在不同时间尺度对大气强迫有何反应？时间谱和空间模式与其物理和生物驱动力以及它们之间的耦合有何关系？对长期趋势和盆地尺度变化的建模研究表明，溶解氧对物理和生物过程高度敏感，并被建议作为海洋气候变化的示踪剂。然而，对根本原因的机械理解还远未完成，因此需要对氧气变化的大规模模式进行更全面的阐明，特别是在新数据迅速增加的情况下。研究小组假设，氧气变化的物理和生物驱动因素是由上层海洋的温跃层通风调节的，从而导致大规模、低频变化的增强。该理论提出了新的假设，用于解释两个反复出现的普遍观察结果：氧气变化在十年时间尺度上如此普遍，并且集中在占据水柱中常见位置的水域，即通风温跃层的底部。他们计划使用一系列模型来评估这些预测，从一维等重模型到具有生态系统和生物地球化学成分的最先进的允许涡流的全球海洋模型。该工作计划将涉及模型层次结构的模式比较，阐明海洋氧循环的基本和非模型相关动力学。该项目的最终成果是将我们的理论和建模方法应用于观测系统模拟实验 (OSSE)，以实现 ARGO-O2 项目的全球实施，以制定未来的观测策略。这将是朝着构建一套工具以了解现实世界中发现的氧气变化类型迈出的重要一步，并为分析这一重要示踪剂的广泛观测和建模数据奠定基础。更广泛的影响：研究人员预计这项工作将揭示缺氧这一新出现的海洋问题，对渔业管理者和海洋保护工作具有战略重要性。通过拟议的 OSSE，该项目将协助制定最佳观测策略，以促进国际社会在 ARGO 浮标上开发全球 O2 传感器阵列的努力。预计结果还将为估计此类不规则采样网络造成的全球范围的氧气损失提供机械基础，从而减少陆地和海洋之间人为二氧化碳吸收分配量化的关键不确定性。最后，该项目将为两名研究生提供培训和支持，并通过研究生和公众在科洛多雕像大学为 K-12 学生开展有关海洋和气候科学的外展活动。