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

在这个项目中，加州大学洛杉矶分校和科罗拉多州立大学的海洋模拟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。近年来对海洋上层氧含量的年代际变化的观测，在每个海盆都有记录，这激发了一些关于潜在机制的问题。溶解氧在不同时间尺度上对大气强迫的响应？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？关于长期趋势和流域尺度变化的建模研究表明，溶解氧对物理和生物过程都非常敏感，并被认为是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，因此需要更充分地阐明氧气变化的大规模模式，特别是随着新数据的迅速增加。研究小组假设，氧气变化的物理和生物驱动因素受到上层海洋温跃层通风的调制，导致大规模低频变化增强。该理论导致新的假设来解释两个经常性的和一般的意见：O2的变化是如此普遍，在十年的时间尺度，并集中在沃茨占据一个共同的位置，在水柱，即基础的通风温跃层。他们计划使用一系列模型来评估这些预测，这些模型从一维等密度模型到最先进的允许涡流的全球海洋模型，包括生态系统和海洋地球化学成分。该工作计划将涉及模式的层次结构的比较，照亮基本的和非模型依赖的海洋氧循环动力学。该项目的高潮是我们的理论和建模方法的观测系统模拟实验（OSSEs）的建议全球实施ARGO-O2项目，以制定未来的观测战略的应用。这将是朝着建立一套工具来理解在真实的世界中发现的O2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是海洋中一个新出现的问题，对渔业管理人员和海洋保护工作具有战略重要性。该项目将通过拟议的开放式观测和安全系统，协助制定最佳观测战略，促进国际上开发实时地转海洋学阵列浮标上的全球氧气传感器阵列的努力。预计这些结果还将提供一个机制的基础，估计全球规模的O2损失，从这种不规则的采样网络，从而减少了一个关键的不确定性，在量化的分配人为CO2吸收之间的土地和海洋。最后，该项目将为两名刚开始学习的研究生提供培训和支助，并在科洛阿多雕像大学为K-12研究生和一般公众开展海洋和气候科学外联活动。

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.