Testing model estimates of recent ocean carbon uptake and deoxygenation using atmospheric and oceanic data

使用大气和海洋数据测试近期海洋碳吸收和脱氧的模型估计

• 批准号: 1130976
• 负责人: Ralph Keeling
• 金额: $ 48.06万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-10-01 至 2015-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1130976&HistoricalAwards=false
• 关键词: Testing; model; estimates; recent; ocean

Model studies suggest that global warming may reduce the ocean uptake of CO2 via changes in ocean circulation and carbon chemistry and lead to reductions of dissolved O2 in the ocean interior, causing an expansion of O2 minimum zones. These processes are possibly already underway in response to warming and wind changes over the past few decades. In this project, researchers at the Scripps Institution of Oceanography will test ocean model simulations of air-sea O2 and CO2 exchange using an approach emphasizing constraints from combined measurements of atmospheric O2/N2 ratio and CO2 concentrations and ocean measurements of chloro-fluorocarbons (CFCs). The approach is based on computing tracer "atmospheric potential oxygen" (APO), which is effectively the weighted sum O2 + 1.1CO2. By construction, APO is insensitive to land biospheric exchanges of CO2 and O2. Observations by the Scripps and Princeton O2 programs show that APO has decreased over the past two decades at a precisely measured rate. Two components of the APO decrease are well understood: (1) a fossil-fuel component and (2) a component related to uptake of anthropogenic CO2 by the oceans, which can be estimated based on ocean observations of CFCs. These two components can both be precisely quantified, and together appear to overestimate the observed APO decrease. The residual APO change constrains the air-sea exchanges of O2 and CO2 not counted as anthropogenic, i.e. due to climate impacts on the oceans. The APO trend is thus directly relevant to quantifying ongoing changes in ocean CO2 and O2. A core activity of this proposal will involve developing and applying data targets for model validation based on the observed APO changes. Working closely with four ocean modeling groups, the Scripps researchers will acquire output of model runs that simulate air-sea exchange of O2 and CO2 over the past few decades in response to climate changes and rising CO2. They will test not only the ability of the models to account for the long-term trends in APO but also for the seasonal cycles, which relate to the processes controlling O2 exchange at middle and high latitudes. Broader Impacts: This work will help to solidify the scientific understanding of two looming and related environmental threats: climate amplification of rising CO2 and ocean deoxygenation. It will also complement ongoing measurement activities of the Scripps O2 program by sustaining a small but viable modeling component. The project will enable dissemination of cutting edge research to the public at large through public presentations and will help foster young talent through support for a young scientist and a graduate student.

模型研究表明，全球变暖可以通过变化海洋循环和碳化学的变化来减少CO2的海洋吸收，并导致海洋内部溶解的O2减少，从而导致O2最小区域的扩大。在过去的几十年中，这些过程可能已经在响应变暖和风变化而进行。在该项目中，Scripps海洋学研究人员将使用一种方法来测试海洋模型O2和CO2交换的海洋模型模拟，该方法强调了大气O2/N2比率合并测量的限制，以及CO2浓度以及对氯氟化合物（CFCS）的浓度的浓度和海洋测量。该方法基于计算示踪剂“大气电势氧”（APO），实际上是加权总和O2 + 1.1CO2。通过构造，APO对CO2和O2的土地生物圈交换不敏感。 Scripps和Princeton O2计划的观察表明，在过去的二十年中，Apo以精确的速度下降。充分了解了Apo降低的两个组成部分：（1）化石燃料成分和（2）与海洋吸收人为CO2相关的成分，可以根据CFC的海洋观察来估计，这可以估算。这两个组件都可以精确量化，并且似乎高估了观察到的Apo减少。残留的APO变化限制了O2和CO2的空气交换不被认为是人为的，即由于气候对海洋的影响。因此，APO趋势与量化海洋CO2和O2的持续变化直接相关。该提案的核心活动将涉及根据观察到的APO变化开发和应用数据目标进行模型验证。 Scripps研究人员与四个海洋建模组紧密合作，将获得模型运行的输出，这些模型在过去几十年中模拟了O2和CO2的空气海洋交换，以响应气候变化和二氧化碳的增加。他们不仅将测试模型的能力，包括APO的长期趋势，还将测试与控制中和高纬度的O2交换过程有关的季节性周期的能力。更广泛的影响：这项工作将有助于巩固对两种迫在眉睫和相关环境威胁的科学理解：二氧化碳和海洋脱氧的气候扩增。它还将通过维持一个小但可行的建模组件来补充Scripps O2程序的正在进行的测量活动。该项目将通过公开演讲将尖端研究传播给公众，并通过支持年轻的科学家和研究生来帮助培养年轻的人才。