Decomposition of Deglacial Pacific Radiocarbon Age Controls Using an Isotope‐Enabled Ocean Model
Decomposition of Deglacial Pacific Radiocarbon Age Controls Using an Isotope‐Enabled Ocean Model
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DOI：
10.1029/2021pa004363
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发表时间：
2022-07
影响因子：
3.5
通讯作者：
Hannah Zanowski;A. Jahn;Sifan Gu;Zhengyu Liu;T. Marchitto
中科院分区：
文献类型：
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作者：
Hannah Zanowski;A. Jahn;Sifan Gu;Zhengyu Liu;T. Marchitto
在最后一次冰消期，地球的气候经历了强烈和突然的变化，导致全球温度，海平面和海洋环流的重大变化。虽然代用记录大大提高了我们对这一时期气候的认识，但海洋环流演变与由此产生的地质示踪剂分布之间的联系，包括太平洋深水沃茨的分布，仍然存在问题。在这里，我们使用C-iTRACE模拟，一个短暂的海洋，同位素启用版本的社区地球系统模型，以更好地了解冰消期深太平洋放射性碳的演变在循环和水库年龄变化的背景下。在整个冰消期，C-iTRACE中的太平洋环流对冰川融水的强迫反应强烈，导致太平洋深部Δ 14 C年龄发生了巨大变化。从20到15 ka BP，翻转环流的数千年减弱导致太平洋深部Δ 14 C年龄增加，但从20到18 ka BP，近一半（40%-60%）的这种年龄是由变化的表面水库年龄控制的，证实了以前的研究表明Δ 14 C不仅仅是一个循环年龄示踪剂。随着冰消作用的进行，环流变化对Δ 14 C年龄的控制作用逐渐增强，在15 ~ 8 kaBP之间占整个太平洋深部Δ 14 C年龄的75%以上。
During the last deglaciation Earth’s climate experienced strong and abrupt variations, resulting in major changes in global temperature, sea level, and ocean circulation. Although proxy records have significantly improved our understanding of climate during this period, questions remain regarding the connection between ocean circulation evolution and resulting geotracer distributions, including those of deep waters in the Pacific. Here we use the C‐iTRACE simulation, a transient ocean‐only, isotope‐enabled version of the Community Earth System Model, to better understand deglacial deep Pacific radiocarbon evolution in the context of circulation and reservoir age changes. Throughout the deglaciation, the Pacific Ocean circulation in C‐iTRACE responds strongly to glacial meltwater forcing, leading to large changes in deep Pacific Δ14C age. A multi‐millennial weakening of the overturning circulation from 20 to 15 ka BP leads to increases in deep Pacific Δ14C ages, but from 20 to 18 ka BP, nearly half (40%–60%) of this aging is controlled by changing surface reservoir age, corroborating previous studies showing that Δ14C is not solely a circulation age tracer. As the deglaciation proceeds, circulation change controls progressively more of the Δ14C age, accounting for more than 75% of it across the deep Pacific from 15 to 8 ka BP.