NSFGEO-NERC: Collaborative Research: Exploring AMOC controls on the North Atlantic carbon sink using novel inverse and data-constrained models (EXPLANATIONS)

海洋在减缓气候变化方面发挥着至关重要的作用，目前大约吸收了排放到大气中的二氧化碳排放量的25%，在长期稳定状态下有可能吸收90%以上。北大西洋吸收了不成比例的这种碳。大西洋子午线翻转环流(AMOC)及其与生物地球化学过程和海洋生态系统的相互作用是决定北大西洋碳汇强度和变异性的关键因素。尽管碳循环模型被用来理解这些过程并预测未来的碳吸收，但这些模型往往不受数据限制，可以产生不同的结果。这使得人们很难对未来的气候预测抱有信心。该项目旨在通过以下方式解决这一问题：1)使用新获得的数据和数值方法估计北大西洋碳的吸收、运输和储存；2)量化AMOC在推动海洋碳汇变异性方面的作用。研究成果将与科学界和公众广泛分享。该项目将支持一个早期职业研究团队，其中包括美国和英国的博士后研究人员。最终，这项工作将向负责向政策制定者传播气候科学的人提供具有不确定性的关键产品，并改进数值模型，以便更准确地预测气候变化。这是一个由国家科学基金会地球科学局(NSF/GEO)和英国国家环境研究委员会(NERC)通过NSF/GEO-NERC牵头机构协议共同资助的项目。该协定允许美国和英国提交一个单一的联合提案，并由该机构进行同行审查，该机构的调查员在预算中所占比例最大。在成功地共同确定一项奖项建议后，每个机构将资助其各自国家机构中支持科学家的预算比例。该项目团队将使用新的方法，将现有的观测约束(来自RAPID和OSNAP系泊的时间序列和重复的船舶横断面)与尖端模型相结合，对北大西洋的碳吸收、运输和储存进行估计。主要目的是探索各种因素在碳汇变异性中的作用，并区分稳态和非稳态过程的贡献。他们将侧重于1990年以来的一段时间，并审查不同观测结果的一致性、AMOC和海洋生态系统的影响，以及自然碳通量在推动北大西洋碳汇变异性方面的作用。该团队将采用一种综合方法，使用反向建模、海洋状态估计、海洋生物地球化学模型和气候模型输出。这种方法将产生多种互补的产品，用于估计北大西洋的碳吸收、运输和储存，并有助于确定AMOC在海洋碳汇时空变异性中的角色。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The ocean plays a vital role in mitigating climate change, currently absorbing roughly 25% of carbon dioxide emissions released into the atmosphere, with the potential to absorb more than 90% at long-term steady state. The North Atlantic Ocean absorbs a disproportionate amount of this carbon. The Atlantic Meridional Overturning Circulation (AMOC), along with its interactions with biogeochemical processes and ocean ecosystems, are key factors in determining the strength and variability of the North Atlantic carbon sink. Although carbon cycle models are used to understand these processes and predict future carbon uptake, these models are often not data-constrained and can produce differing results. This makes it difficult to have confidence in future climate projections. This project aims to address this by 1) estimating the uptake, transport, and storage of carbon in the North Atlantic using newly-available data and numerical methods and 2) quantifying the role of AMOC in driving ocean carbon sink variability. The research results will be shared broadly with the scientific community and the general public. The project will support a team of early career investigators, including postdoctoral researchers in the US and UK. Ultimately, this work will deliver key products with uncertainties to those responsible for disseminating climate science to policymakers, and improve numerical models for more accurate projections of climate change. 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 project team will produce estimates of carbon uptake, transport, and storage in the North Atlantic using novel approaches that combine available observational constraints (from RAPID and OSNAP moored time series and repeat ship transects) with cutting-edge models. The main goal is to explore the role of various factors in carbon sink variability and to separate contributions due to steady-state and non-steady-state processes. They will focus on the period since 1990 and examine the consistency of different observations, the impact of the AMOC and ocean ecosystems, and the role of natural carbon fluxes in driving North Atlantic carbon sink variability. The team will adopt an integrated approach that uses inverse modeling, ocean state estimates, ocean biogeochemical models, and climate model output. This approach will produce multiple complementary products for estimating carbon uptake, transport, and storage in the North Atlantic and help determine the AMOC's role in ocean carbon sink space-time variability.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.