NSFGEO-NERC: Collaborative Research: Role of the Overturning Circulation in Carbon Accumulation (ROCCA)

北大西洋在全球碳循环中发挥着重要作用，它吸收了不成比例的大量人类二氧化碳排放。这些点被认为与大西洋经向翻转环流（AMOC）密切相关，但海气通量和海洋输送对北大西洋碳积累的贡献平衡并没有得到很好的限制。未来的情况存在很大的不确定性，无论是AMOC强度还是碳吸收，因为它们对气候变化和其他变化的影响做出了反应。该项目将利用整个北大西洋盆地的长期和持续观测，以量化碳吸收和碳运输以及这些参数在数十年时间尺度上的变化。这项工作将支持各种努力，教育和促进海洋科学中代表性不足的群体。项目调查人员将与格鲁吉亚、佛罗里达和加勒比地区的各种机构合作，对学生进行各种水平的教育。他们将推广一个碳循环教育网站，其中包括互动的K-12教育材料。这是一个由国家科学基金会地球科学理事会（NSF/GEO）和联合王国国家环境研究理事会（NERC）通过NSF/GEO-NERC牵头机构协议联合资助的项目。该协议允许美国/英国提交一份联合提案，并由研究者拥有最大预算比例的机构进行同行评审。在成功共同确定奖励建议后，每个机构将资助各自国家机构科学家的预算比例。ROCCA项目旨在重新定义我们对北大西洋碳系统的理解，北大西洋碳系统是世界上最重要的碳封存区域之一，具有重要的气候意义。该团队将使用对亚热带和亚极地区域人为碳传输的新估计，以确定海气通量和海洋环流对区域碳积累的贡献，这是一个基本的知识空白。随着倾覆强度预计减弱，该分析将能够评估它们对未来碳吸收的综合影响。在佛罗里达海峡的新观测将首次全面表征水团结构在季节时间尺度上的化学变化，并结合来自运输发散/积累预算的海气人为CO2通量，该团队将验证现有的数值模拟，并改善下一代气候模型中碳循环过程的代表性。具体的研究目标是1.计算26°N RAPID阵列（2004 - 2024年）和副极地OSNAP剖面（2014-2024年）的人为碳输送，包括对AMOC变化的敏感性; 2.制作北大西洋人为碳清单变化的时间序列; 3.海气人为碳通量时间序列的积累（O 1）和运输分歧（O2）; 4。约束对未来变化的预测，并确定人为碳运输/ AMOC指标; 5.该奖项反映了NSF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。

The North Atlantic Ocean plays an important role in the global carbon cycle, and it absorbs a disproportionately high amount of human carbon dioxide emissions. These points are thought to be closely related to the Atlantic Meridional Overturning Circulation (AMOC), but the balance of contributions to North Atlantic carbon accumulation from air-sea fluxes and ocean transports is not well constrained. There is significant uncertainty about what the future holds, both for AMOC strength and carbon uptake as they respond to the effects of climate change and other changing forcings. This project will utilize long-term and ongoing observations across the North Atlantic basin to quantify carbon uptake and carbon transport and the variability in these parameters on the time scale of decades. This work will support a variety of efforts to educate and promote underrepresented groups in ocean science. The project investigators will partner with a variety of institutions in Georgia, Florida and in the Caribbean to educate students at a range of levels. They will promote a carbon cycle education website that includes interactive K-12 education materials. This is a project jointly funded by the National Science Foundation’s Directorate for Geosciences (NSF/GEO) and the National Environment Research Council (NERC) of the United Kingdom (UK) via the NSF/GEO-NERC Lead Agency Agreement. This Agreement allows a single joint US/UK proposal to be submitted and peer-reviewed by the Agency whose investigator has the largest proportion of the budget. Upon successful joint determination of an award recommendation, each Agency funds the proportion of the budget that supports scientists at institutions in their respective countries.The ROCCA project aims to redefine our understanding of the North Atlantic carbon system, one of the world’s most important regions for carbon sequestration on climatically-important timescales. The team will use new estimates of anthropogenic carbon transports across both subtropical and subpolar domains to determine the contributions of air-sea fluxes and ocean circulation to regional carbon accumulation, a fundamental knowledge gap. This analysis will enable evaluation of their combined effects on future carbon uptake as overturning strength is projected to weaken. New observations in Florida Straits will fully characterize the chemical variability in water mass structure on seasonal timescales for the first time, and in combination with air-sea anthropogenic CO2 fluxes derived from transport-divergence/accumulation budgets, the team will validate existing numerical simulations and improve the representation of carbon cycle processes in the next generation of climate models. The specific research objectives are to 1. Calculate anthropogenic carbon transports across the RAPID array at 26°N (2004 to 2024) and the subpolar OSNAP section (2014-2024), including sensitivity to AMOC changes; 2. Produce time-series of changing anthropogenic carbon inventory in the North Atlantic; 3. Air-sea anthropogenic carbon flux timeseries from accumulation (O1) and transport divergence (O2); 4. Constrain projections of future change and identify anthropogenic carbon transport / AMOC metrics; and 5. Assess the uncertainty of components of the observational approach, applying them to high-resolution model outputs.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.