North Atlantic ventilation of "southern-sourced" deep water in the glacial ocean
North Atlantic ventilation of "southern-sourced" deep water in the glacial ocean
复制标题
冰川海洋中“南源”深水的北大西洋通风
DOI：
10.1029/2011pa002211
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
J. Toggweiler
中科院分区：
文献类型：
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作者：
E. Kwon;M. Hain;D. Sigman;E. Galbraith;J. Sarmiento;J. Toggweiler
冰河时期降低大气二氧化碳排放的一种潜在机制是北大西洋通风的全球海洋比例增加，北大西洋产生的深水含有低浓度的未使用营养物质，从而驱动海洋生物泵达到高效率。然而，数据表明，在冰河时期，13C/12C和14C/C的低水团占据了大西洋深处，显然是以北大西洋深水（NADW）为代价的。这种水通常被称为“南方水源”，因为它显然是从南方进入大西洋盆地的，这促使人们推断它是在南大洋表面通风的。在这里，我们提出，大西洋深水团实际上包括北大西洋通风水的很大一部分，其化学特性因南太平洋深海和印度太平洋的再循环而改变。在一项减少南极底水形成并削弱其翻转环流的海洋模型敏感性实验中，我们发现很大一部分NADW在不接触海面的情况下被输送到南大洋，并被夹带和混合到来自南部的深水中，然后扩散到全球深海中。因此，北大西洋的通风占据了更多的海洋内部，降低了大气中的二氧化碳含量，但大西洋深海却充满了来自南方的13C/12C和14C/C的旧水，这与冰川数据一致。
One potential mechanism for lowering atmospheric CO2 during glacial times is an increase in the fraction of the global ocean ventilated by the North Atlantic, which produces deep water with a low concentration of unused nutrients and thus drives the ocean's biological pump to a high efficiency. However, the data indicate that during glacial times, a water mass low in 13C/12C and 14C/C occupied the deep Atlantic, apparently at the expense of North Atlantic Deep Water (NADW). This water is commonly referred to as “southern-sourced” because of its apparent entry into the Atlantic basin from the South, prompting the inference that it was ventilated at the Southern Ocean surface. Here, we propose that this deep Atlantic water mass actually included a large fraction of North Atlantic-ventilated water, the chemical characteristics of which were altered by recirculation in the deep Southern and Indo-Pacific oceans. In an ocean model sensitivity experiment that reduces Antarctic Bottom Water formation and weakens its overturning circulation, we find that a much greater fraction of NADW is transported into the Southern Ocean without contacting the surface and is entrained and mixed into the southern-sourced deep water that spreads into the global abyssal ocean. Thus, North Atlantic ventilation takes over more of the ocean interior, lowering atmospheric CO2, and yet the abyssal Atlantic is filled from the South with old water low in 13C/12C and 14C/C, consistent with glacial data.
影响因子：
56.9
作者：
J. Lynch‐Stieglitz;J. Adkins;W. Curry;T. Dokken;I. Hall;J. Herguera;J. Hirschi;E. Ivanova;
通讯作者：
J. Lynch‐Stieglitz;J. Adkins;W. Curry;T. Dokken;I. Hall;J. Herguera;J. Hirschi;E. Ivanova;
影响因子：
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作者：
de Boer, A. M.;Sigman, D. M.;Russell, J. L.
通讯作者：
Russell, J. L.