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，目前吸收了大约25%的排放到大气中的二氧化碳，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碳。大西洋经向翻转环流（AMOC），沿着其与海洋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可变性的关键因素。虽然碳循环模型被用来理解这些过程并预测未来的碳吸收，但这些模型通常不受数据约束，可能会产生不同的结果。这使得人们很难对未来的气候预测有信心。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在驱动海洋碳汇变化方面的作用。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调查团队，包括美国和英国的博士后研究人员。最终，这项工作将为负责向决策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。一旦成功地共同确定了一项奖励建议，每个机构就为支助各自国家机构科学家的预算部分提供资金。该项目小组将使用新方法对北大西洋的碳吸收、运输和储存进行估计，这些新方法将现有的观测约束（来自RAPID和OSNAP系泊时间序列和重复船舶断面）与尖端模型相结合。主要目标是探讨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年以来的时期，并审查不同观测的一致性，AMOC和海洋生态系统的影响，以及自然碳通量在驱动北大西洋碳汇变化方面的作用。该团队将采用一种综合方法，使用逆向建模，海洋状态估计，海洋地球化学模型和气候模型输出。该方法将产生多种互补产品，用于估算北大西洋的碳吸收、运输和储存，并帮助确定AMOC在海洋碳汇时空变化中的作用。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 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.