Abstract Reconstructing the Atlantic Meridional Overturning Circulation (AMOC) during the Last Glacial Maximum (LGM) is essential for understanding glacial-interglacial climate change and the carbon cycle. However, despite many previous studies, uncertainties remain regarding the glacial water mass distributions in the Atlantic and the AMOC intensity. Here we use an isotope enabled ocean model with multiple geotracers ( δ 13 C , e N d , 231Pa/230Th, δ 18 O and Δ 14 C) and idealized water tracers to study the potential constraints on LGM ocean circulation from multiple proxies. Our model suggests that the glacial Atlantic water mass distribution can be accurately constrained by the air-sea gas exchange signature of water masses ( δ 13 C A S ), but e N d might overestimate the North Atlantic Deep Water (NADW) percentage in the deep Atlantic probably because of the boundary source of Nd. A sensitivity experiment with an AMOC of similar geometry but much weaker strength suggests that the correct AMOC geometry is more important than the AMOC strength for simulating the observed glacial δ 13 C and e N d distributions. The kinematic tracer 231Pa/230Th is sensitive to AMOC intensity, but the interpretation might be complicated by the AMOC geometry and AABW transport changes during the LGM. δ 18 O in the benthic foraminifera ( δ 18 O c ) from the Florida Straits provides a consistent measure of the upper ocean boundary current in the model, which potentially provides an unambiguous method to reconstruct glacial AMOC intensity. Finally, we propose that the moderate difference between AMOC intensity at LGM and PD, if any, is caused by the competition of the responses to CO2 forcing and continental ice sheet forcing.

中文翻译：

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在 CESM 中使用多个代理评估重建冰川大西洋水团和 AMOC 的潜在能力

摘要 重建末次盛冰期 (LGM) 期间的大西洋经向翻转环流 (AMOC) 对于了解冰期-间冰期气候变化和碳循环至关重要。然而，尽管有许多先前的研究，大西洋冰川水质量分布和 AMOC 强度仍然存在不确定性。在这里，我们使用具有多个地质示踪剂（δ 13 C 、e N d 、231Pa/230Th、δ 18 O 和 Δ 14 C）和理想化水示踪剂的同位素启用海洋模型来研究来自多个代理的 LGM 海洋环流的潜在限制。我们的模型表明，冰川大西洋水团的分布可以通过水团的海气交换特征（δ 13 CAS）来精确约束，但 e N d 可能高估了大西洋深处的北大西洋深水 (NADW) 百分比，这可能是因为 Nd 的边界来源。对具有相似几何形状但强度要弱得多的 AMOC 进行的敏感性实验表明，对于模拟观测到的冰川 δ 13 C 和 e N d 分布，正确的 AMOC 几何形状比 AMOC 强度更重要。运动示踪剂 231Pa/230Th 对 AMOC 强度敏感，但在 LGM 期间 AMOC 几何形状和 AABW 输运变化可能会使解释变得复杂。来自佛罗里达海峡的底栖有孔虫 (δ 18 O c ) 中的 δ 18 O 提供了模型中上层海洋边界流的一致测量值，这可能为重建冰川 AMOC 强度提供了一种明确的方法。最后，