Quantifying mechanisms of variability in ocean CO2 uptake 1980-present

1980 年至今海洋二氧化碳吸收变化的量化机制

• 批准号: 1948955
• 负责人: Timothy DeVries
• 金额: $ 36.41万
• 依托单位: University of California-Santa Barbara
• 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: 2020-07-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1948955&HistoricalAwards=false
• 关键词: Quantifying; mechanisms; variability; ocean; CO2

Over time, the ocean has absorbed roughly one third of all human carbon dioxide (CO2) emissions due to fossil fuel burning and deforestation. However, observations show that the rate at which the ocean absorbs CO2 from the atmosphere can vary greatly from one year to the next, and on even longer timescales. These variations result from some combination of natural and human-caused climate variability, but our understanding of the reasons for this variability remains incomplete, which hampers our understanding of the global carbon budget and hinders our ability to make accurate climate forecasts. In this project, we will perform targeted experiments with several different state-of-the-art models of the ocean carbon cycle to determine what factors are responsible for variability in the rate of CO2 uptake by the ocean over the past four decades. These experiments will determine which models best represent the important climate processes driving variability in ocean CO2 uptake, and will identify areas where the models can be improved, which will lead to better constraints on the climate sensitivity of ocean carbon uptake, and lead to better climate projections. This work will also help to identify how and why the variability of CO2 uptake in models differs from the observations and help to resolve imbalances in the global carbon budget. Finally, this will lead to improved constraints on CO2 emissions to limit the damaging effects of global warming. The broader impacts of this work include the training of a graduate student in ocean carbon cycle modeling, and training of two undergraduate students from historically black colleges and universities.The ocean is one of the two main sinks for anthropogenic CO2 emissions (the terrestrial biosphere being the other) and absorbs roughly 25% of current anthropogenic CO2 emissions. Recent work has shown that the variability of the ocean CO2 sink rivals that of the terrestrial CO2 sink on decadal timescales, but the mechanisms driving this variability remain unclear. Identifying the drivers of variability in the ocean CO2 sink is important for understanding how the ocean carbon sink will respond to future climate changes, for developing more accurate prognostic climate models, and for reconciling decadal imbalances in the global carbon budget. This project will undertake targeted simulations with ocean biogeochemical models and ocean inverse models to answer the overarching science question: “What are the drivers of interannual to decadal variability in the ocean CO2 sink over the past four decades?” To answer this question this work focusses on three main objectives: (i) quantifying mechanisms of variability in ocean CO2 uptake over the past four decades in a suite of ocean biogeochemical models and an ocean circulation inverse model, (ii) comparing across models and methods to determine the most robust mechanisms driving variability in ocean CO2 uptake at both global and regional scales, and (iii) comparing the variability of ocean CO2 uptake in biogeochemical models and ocean inverse models to determine which models and mechanisms best agree with the observations. This work will determine which models best represent the important processes driving variability in ocean CO2 uptake and will identify areas where the models can be improved. This work will also help to identify how and why the variability of CO2 uptake in models differs from the observations, and help to resolve imbalances in the global carbon budget. Last, our results will lead to an improved mechanistic understanding of variability in the ocean carbon sink, which will lead to better constraints on the climate sensitivity of ocean carbon uptake, and to better climate projections.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.

随着时间的推移，由于化石燃料燃烧和森林砍伐，海洋吸收了大约三分之一的人类二氧化碳排放。然而，观测表明，海洋从大气中吸收二氧化碳的速率在一年与下一年之间，甚至在更长的时间尺度上，可能会有很大的变化。这些变化是由自然和人为引起的气候变率的某种组合造成的，但我们对这种变率的原因的理解仍然不完整，这阻碍了我们对全球碳收支的理解，并阻碍了我们做出准确气候预报的能力。在这个项目中，我们将用几种不同的最先进的海洋碳循环模型进行有针对性的实验，以确定在过去的四十年中，是什么因素导致了海洋二氧化碳吸收率的变化。这些实验将确定哪些模式最能代表驱动海洋二氧化碳吸收变率的重要气候过程，并将确定模式可以改进的领域，这将更好地限制海洋碳吸收的气候敏感性，并导致更好的气候预测。这项工作还将有助于确定模式中二氧化碳吸收的变异性如何以及为什么与观测值不同，并有助于解决全球碳预算的不平衡问题。最后，这将改善对二氧化碳排放的限制，以限制全球变暖的破坏性影响。这项工作的更广泛影响包括培训一名海洋碳循环建模的研究生，以及培训两名来自历史上黑人学院和大学的本科生。海洋是人为二氧化碳排放的两个主要汇之一（另一个是陆地生物圈），吸收目前大约25%的人为二氧化碳排放。最近的研究表明，在年代际尺度上，海洋二氧化碳汇的可变性与陆地二氧化碳汇的可变性相当，但驱动这种可变性的机制尚不清楚。确定海洋二氧化碳汇变率的驱动因素对于了解海洋碳汇如何响应未来气候变化、开发更准确的预测气候模式以及协调全球碳收支的年代际失衡具有重要意义。该项目将使用海洋生物地球化学模型和海洋逆模型进行有针对性的模拟，以回答一个首要的科学问题：“在过去40年里，海洋二氧化碳汇的年际到年代际变化的驱动因素是什么？”为了回答这个问题，这项工作集中在三个主要目标上：(i)在一套海洋生物地球化学模式和一个海洋环流逆模式中量化过去40年海洋二氧化碳吸收变率的机制；（ii）在各种模式和方法之间进行比较，以确定全球和区域尺度上驱动海洋二氧化碳吸收变率的最有力机制；（iii）比较生物地球化学模式和海洋逆模式中海洋二氧化碳吸收的变率，以确定哪种模式和机制最符合观测结果。这项工作将确定哪些模型最能代表驱动海洋二氧化碳吸收变化的重要过程，并将确定模型可以改进的领域。这项工作还将有助于确定模式中二氧化碳吸收的变异性如何以及为什么与观测值不同，并有助于解决全球碳预算的不平衡问题。最后，我们的研究结果将有助于提高对海洋碳汇变异性的机制理解，从而更好地限制海洋碳吸收的气候敏感性，并更好地预测气候。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Data-based estimates of interannual sea–air CO₂ flux variations 1957–2020 and their relation to environmental drivers

基于数据的 1957 年至 2020 年海气 CO₂ 通量变化及其与环境驱动因素的关系的估计

• DOI: 10.5194/bg-19-2627-2022
• 发表时间: 2022
• 期刊: Biogeosciences
• 影响因子: 4.9
• 作者: Rödenbeck, Christian;DeVries, Tim;Hauck, Judith;Le Quéré, Corinne;Keeling, Ralph F.
• 通讯作者: Keeling, Ralph F.

Source‐Labeled Anthropogenic Carbon Reveals a Large Shift of Preindustrial Carbon From the Ocean to the Atmosphere

来源——标记的人为碳揭示了工业化前碳从海洋到大气的大规模转移

• DOI: 10.1029/2022gb007405
• 发表时间: 2022
• 期刊: Global Biogeochemical Cycles
• 影响因子: 5.2
• 作者: Holzer, Mark;DeVries, Tim
• 通讯作者: DeVries, Tim

Assessing the sequestration time scales of some ocean-based carbon dioxide reduction strategies

评估一些海洋二氧化碳减排策略的封存时间尺度

• DOI: 10.1088/1748-9326/ac0be0
• 发表时间: 2021
• 期刊: Environmental Research Letters
• 影响因子: 6.7
• 作者: Siegel, D A;DeVries, T;Doney, S C;Bell, T
• 通讯作者: Bell, T

Stable Carbon Isotopes Suggest Large Terrestrial Carbon Inputs to the Global Ocean

稳定碳同位素表明全球海洋有大量陆地碳输入

• DOI: 10.1029/2020gb006684
• 发表时间: 2021
• 期刊: Global Biogeochemical Cycles
• 影响因子: 5.2
• 作者: Kwon, Eun Young;DeVries, Tim;Galbraith, Eric D.;Hwang, Jeomshik;Kim, Guebuem;Timmermann, Axel
• 通讯作者: Timmermann, Axel