Global cooling linked to increased glacial carbon storage via changes in Antarctic sea ice
Global cooling linked to increased glacial carbon storage via changes in Antarctic sea ice
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全球变冷与南极海冰变化导致冰川碳储存增加有关
DOI：
10.1038/s41561-019-0466-8
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发表时间：
2019
影响因子：
18.3
通讯作者：
M. Jansen
中科院分区：
文献类型：
--
作者：
A. Marzocchi;M. Jansen
古海洋学重建表明，在过去的250万年里，全球海洋水团的分布经历了重大的冰川-间冰期重排。鉴于海洋是最大的碳库，这种环流变化可能是驱动冰芯记录中观察到的大气CO2浓度变化的关键。然而，我们仍然缺乏对海洋在这些时间尺度上调节二氧化碳的作用的机械理解。在这里，我们表明，冰川海洋海冰数值模拟与单盆地环流模型，迫使仅由大气冷却，可以预测海洋环流模式与增加大气中的深海碳封存。在这种情况下，由于两个相互关联的因素，南极底层水变得更加孤立于海面：南极洲周围海冰下的气-海气体交换减少，以及由于南北源水团之间的界面较浅，与北大西洋深水的混合较弱。仅这些物理变化就足以解释约40 ppm的大气CO2下降-约一半的冰川-间冰期变化。我们的研究结果强调，大气冷却可能直接导致深海水体的重组，从而导致冰川CO2下降。根据海洋-海冰和海洋地球化学耦合数值模型，由于表面冷却，南极洲周围的深水被隔离，这可以解释冰川-间冰期循环造成的大气CO2水平变化的一半。
Palaeo-oceanographic reconstructions indicate that the distribution of global ocean water masses has undergone major glacial–interglacial rearrangements over the past ~2.5 million years. Given that the ocean is the largest carbon reservoir, such circulation changes were probably key in driving the variations in atmospheric CO2 concentrations observed in the ice-core record. However, we still lack a mechanistic understanding of the ocean’s role in regulating CO2 on these timescales. Here, we show that glacial ocean–sea ice numerical simulations with a single-basin general circulation model, forced solely by atmospheric cooling, can predict ocean circulation patterns associated with increased atmospheric carbon sequestration in the deep ocean. Under such conditions, Antarctic bottom water becomes more isolated from the sea surface as a result of two connected factors: reduced air–sea gas exchange under sea ice around Antarctica and weaker mixing with North Atlantic Deep Water due to a shallower interface between southern- and northern-sourced water masses. These physical changes alone are sufficient to explain ~40 ppm atmospheric CO2 drawdown—about half of the glacial–interglacial variation. Our results highlight that atmospheric cooling could have directly caused the reorganization of deep ocean water masses and, thus, glacial CO2 drawdown. This provides an important step towards a consistent picture of glacial climates.Isolation of deep water around Antarctica due to surface cooling can explain half of the change in atmospheric CO2 levels through glacial–interglacial cycles, according to coupled ocean–sea ice and biogeochemical numerical modelling.
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冰川大西洋经向翻转环流的强度和几何形状
影响因子：
18.3
作者：
Lippold;Y. Luo;R. Francois;S. Allen;J. Gherardi;S. Pichat;B. Hickey;H. Schulz
通讯作者：
H. Schulz
影响因子：
13.6
作者：
Khatiwala, S.;Schmittner, A.;Muglia, J.
通讯作者：
Muglia, J.
影响因子：
4
作者：
Gersonde, R;Crosta, X;Armand, L
通讯作者：
Armand, L
影响因子：
5.2
作者：
P. Goodwin;M. Follows;Richard G. Williams
通讯作者：
P. Goodwin;M. Follows;Richard G. Williams
影响因子：
3.2
作者：
Losch, Martin;Menemenlis, Dimitris;Hill, Chris
通讯作者：
Hill, Chris