Collaborative Research: Combining Theory and Observations to Constrain Global Ocean Deoxygenation

合作研究：结合理论和观测来抑制全球海洋脱氧

• 批准号: 1737282
• 负责人: Curtis Deutsch
• 金额: $ 33.4万
• 依托单位: University of Washington
• 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: 2017-09-01 至 2022-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1737282&HistoricalAwards=false
• 关键词: Collaborative; Research; Combining; Theory; Observations

This project will use a combination of ocean observations and modeling to understand why the dissolved oxygen concentration in the ocean changes on timescales of years to decades. As oceans absorb heat, its oxygen content is expected to decline which will affect marine ecosystems and oxygen-sensitive biochemical reactions. In turn, biochemical processes can affect the oxygen level. Understanding why oceanic oxygen changes remains limited due to sparse data and the fact that it naturally fluctuates. Furthermore, state-of-the-art Earth System Models, used to develop future projections, struggle to skillfully simulate present-day oxygen distributions. Given model biases, there is a clear need to re-calibrate model-based projections based on informed interpretations of available observations. The intellectual merit of this study is to perform a series of computational simulations to quantify linkages between the patterns of climate variability, ocean heating, and oxygen content for different regions. In conjunction with a novel synthesis of available observational data, this modeling study will develop a more comprehensive model for evaluating oxygen variability and change, thereby reducing uncertainty in future projections under climate forcing scenarios. Broader impacts of this study includes education and outreach about decreasing ocean concentrations in the ocean and its disruptive impacts on ocean biogeochemical cycles and marine ecosystems. Two Ph.D. students and a postdoctoral scientist will be trained under the supervision of the PIs. Ocean deoxygenation is a direct consequence of ocean heat uptake; as ocean waters warm, dissolved oxygen (O2) concentrations decline, with profound influences on marine ecosystem and redox-sensitive biogeochemical cycling. Existing observations are characterized by significant interannual to decadal fluctuations. Natural variability challenges detection and attribution of human-driven trends; however, it can also be interrogated to provide mechanistic insight. State-of-the-art Earth System Models still struggle to skillfully simulate present-day O2 distributions but these models are useful because they invoke mechanistic representations of key processes. The objective of this project is to improve our understanding of the mechanisms behind interannual and decadal variability of O2 globally and regionally. Low- and high-latitude regions exhibit distinct patterns in dissolved oxygen and ocean heat content. In order to isolate the impact of physical and biological controls on O2 variability, a suite of numerical simulations will be conducted, including some with a global eddy-resolving configuration. Combining observational and model-based analyses will enable quantitative assessments about the relation between ocean heat uptake and deoxygenation, and linkages to climate variability and trends.

该项目将结合海洋观测和建模，以了解为什么在数年到几年的时间尺度上，海洋中溶解的氧气浓度会改变。随着海洋吸收热量，其氧含量预计会下降，这将影响海洋生态系统和氧气敏感的生化反应。反过来，生化过程会影响氧气水平。 了解为什么由于数据稀疏以及自然波动的事实，海洋氧的变化仍然受到限制。此外，最新的地球系统模型用于开发未来的预测，努力熟练地模拟当今的氧气分布。给定模型偏见，显然需要根据可用观察结果的知情解释来重新校准基于模型的预测。这项研究的智力优点是进行一系列计算模拟，以量化不同区域的气候变异性，海洋加热和氧含量之间的联系。结合新的可用观测数据综合，该建模研究将开发出更全面的模型，用于评估氧气变异性和变化，从而减少在气候强迫场景下未来预测的不确定性。这项研究的更广泛的影响包括有关降低海洋浓度的教育和外展，其对海洋生物地球化学周期和海洋生态系统的破坏性影响。两位博士学生和博士后科学家将在PI的监督下接受培训。海洋脱氧是海洋热吸收的直接结果。随着海水的温暖，溶解的氧（O2）浓度下降，对海洋生态系统和对氧化还原敏感的生物地球化学循环产生了深远的影响。现有观察结果的特征是年纪至际波动的显着特征。自然变异性挑战人类驱动趋势的检测和归因；但是，也可以审问以提供机械洞察力。最先进的地球系统模型仍然难以熟练地模拟当今的O2分布，但是这些模型很有用，因为它们调用了关键过程的机理表示。该项目的目的是提高我们对全球和区域内O2际变化背后的机制的理解。低纬度区域在溶解的氧气和海洋热含量中表现出不同的模式。为了隔离物理和生物控制对O2变异性的影响，将进行一套数值模拟，包括一些具有全球涡流构型的构型。结合观察性和基于模型的分析将对海洋热量吸收和脱氧之间的关系以及与气候变化和趋势的联系进行定量评估。