Contemporary oceanic radiocarbon response to ocean circulation changes
Contemporary oceanic radiocarbon response to ocean circulation changes
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DOI：
10.1007/s00382-023-06737-3
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发表时间：
2023-03
期刊：
影响因子：
4.6
通讯作者：
Byju Pookkandy;H. Graven;Adrian P. Martin
中科院分区：
文献类型：
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作者：
Byju Pookkandy;H. Graven;Adrian P. Martin
放射性碳（14 C）是海洋环流的一种有价值的示踪剂，这是由于其数千年的自然衰变以及1950年代和1960年代核武器试验的干扰。以前的研究使用14 C来评估模型或调查过去的气候变化。然而，在过去的几十年中，海洋14 C和海洋环流变化之间的关系还没有被探索。本文利用一个海洋海冰模式（NEMO），在大气14 C和CO2边界条件下，模拟了海洋环流趋势和变化对14 C的影响。我们发现14 C/C（δ 14 C）变异性与潜在密度变异性一般是反相关的。变化最大的区域因深度而异：在表层的上升流区域、300米深的亚热带环流边缘以及1 000米深的南极中层水和北大西洋深层水。我们发现，在大西洋经向翻转环流的趋势可能会影响在北大西洋14 C的趋势。在高变率区域，模拟的变化大于典型海洋14 C测量的2-5‰的不确定度，表明14 C数据可以提供一个有用的环流变化的示踪剂。
Radiocarbon (14C) is a valuable tracer of ocean circulation, owing to its natural decay over thousands of years and to its perturbation by nuclear weapons testing in the 1950s and 1960s. Previous studies have used14C to evaluate models or to investigate past climate change. However, the relationship between ocean14C and ocean circulation changes over the past few decades has not been explored. Here we use an Ocean-Sea-ice model (NEMO) forced with transient or fixed atmospheric reanalysis (JRA-55-do) and atmospheric14C and CO2boundary conditions to investigate the effect of ocean circulation trends and variability on14C. We find that14C/C (∆14C) variability is generally anti-correlated with potential density variability. The areas where the largest variability occurs varies by depth: in upwelling regions at the surface, at the edges of the subtropical gyres at 300 m depth, and in Antarctic Intermediate Water and North Atlantic Deep Water at 1000 m depth. We find that trends in the Atlantic Meridional Overturning Circulation may influence trends in ∆14C in the North Atlantic. In the high-variability regions the simulated variations are larger than typical ocean ∆14C measurement uncertainty of 2–5‰ suggesting that ∆14C data could provide a useful tracer of circulation changes.