Resolving the ocean's role in deglacial radiocarbon cycling (OCEAN-14)

该项目旨在通过使用放射性碳作为碳循环示踪剂，提高我们对全球海洋大尺度环流及其作为大气二氧化碳（CO2）和区域气候的强大调节剂的作用的理解。海洋是一个巨大的、动态的碳和热的储存库，海洋环流的变化可能会极大地改变区域和全球气候的演变。对过去气候变化的研究表明，这种变化是可能发生的，而且确实非常迅速。然而，它们的触发机制及其对碳循环（从而对全球气候）的影响仍然知之甚少。该项目旨在通过在利用放射性碳作为过去海洋-碳循环-气候相互作用窗口方面取得的重大进展，弥合我们对气候系统知识的这些差距。我们的主要科学目标是：1)大幅度提高过去3万年海洋放射性碳观测框架的质量和规模；2)利用这些数据对海洋翻转环流在主要碳循环扰动中的作用施加独特的强大约束，这些扰动导致了末次盛冰期（LGM）的气候及其在末次冰消期的演变。这些目标将通过开发一个高效、经济、雄心勃勃的放射性碳分析计划来实现，包括对特别小的（0.01-0.2mgC当量）碳酸盐样品的放射性碳样品制备方法的完善，生成跨越世界主要海洋盆地和过去3万年的新的放射性碳数据阵列。以及该数据阵列与一套新型海洋环流模式（OGCM）实验和分析的对抗。这种规模和设计的“古海洋”放射性碳调查是完全前所未有的，将改变我们对海洋环流在区域和全球气候变化中的作用的理解，特别是通过对海洋气候动力学的三个绝对基本方面提供独特的见解，这些方面长期以来一直是古海洋学研究的难以捉摸的目标：海洋内部的碳运输速率，与大气的交换速率，以及对区域气候变化的敏感性。

This project aims to improve our understanding of the global ocean's large-scale circulation and its role as a powerful moderator of atmospheric carbon dioxide (CO2) and regional climate, specifically through the use of radiocarbon as a carbon cycle tracer. The ocean represents a vast and dynamic reservoir of carbon, and heat, such that changes in the ocean's circulation may drastically alter the evolution of regional and global climate. Research into past climate change has demonstrated that such changes can occur, and very rapidly indeed. However, their triggering mechanisms and their impacts on the carbon cycle (and therefore global climate) remain poorly understood. This project aims to bridge these gaps in our knowledge of the climate system through a major advance in the use of radiocarbon as a window into past ocean-carbon cycle-climate interactions. Our main scientific goals are: 1) to deliver a major increase in the quality and size of the marine radiocarbon observational framework spanning the last 30,000 years; and 2) to use these data to place uniquely powerful constraints on the role of the ocean's overturning circulation in the major carbon cycle perturbations that contributed to the climate of the Last Glacial Maximum (LGM) and its evolution across the last deglaciation. These goals will be achieved through the development of a highly efficient, cost-effective and ambitious radiocarbon analysis program, involving the prefection of radiocarbon sample prepration methods for especially small (0.01-0.2mgC equivalent) carbonate samples, the generation of a new radiocarbon data array spanning the world's major ocean basins and the last 30,000 years, and the confrontation of this data array with a suite of novel ocean general circulation model (OGCM) experiments and analyses. A 'palaeocean' radiocarbon survey of this scale and design is totally unprecedented and will transform our understanding of the role of the ocean circulation in regional and global climate change, in particular by delivering unique insights into three absolutely fundamental aspects of ocean-climate dynamics that have long remained elusive targets of palaeoceanographic research: the rate of carbon transport in the ocean interior, its rate of exchange with the atmosphere, and its sensitivity to regional climate change.