Demons in the North Atlantic: Variability of Deep Ocean Ventilation
Demons in the North Atlantic: Variability of Deep Ocean Ventilation
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DOI：
10.1029/2020gl092340
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发表时间：
2021-01
影响因子：
5.2
通讯作者：
G. MacGilchrist;H. L. Johnson;C. Lique;David P. Marshall
中科院分区：
文献类型：
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作者：
G. MacGilchrist;H. L. Johnson;C. Lique;David P. Marshall
通过海洋通风将大气强迫变率转换到海洋内部是瞬变气候变化的一个重要方面。在亚热带的季节性时间尺度上，这种转换是由所谓的“恶魔”调节的，它阻止了除冬末混合层水以外的所有水的进入。在这里，我们使用一个允许涡流的数值环流模式来研究一个在北大西洋次极地较长(年际)时间尺度上运行的类似过程。我们发现，大气强迫的变化在其向海洋内陆的转移中起到了中介作用，而冬末混合层深度的年际变化是关键因素。当强迫停止时，驱动深层混合层的持续强大气强迫的特征优先向内部输送。对这种影响的敏感性取决于俯冲的位置和密度--新通风的水逃离其俯冲区域的速度是关键因素。
Translation of atmospheric forcing variability into the ocean interior via ocean ventilation is an important aspect of transient climate change. On a seasonal timescale in the subtropics, this translation is mediated by a so‐called “Demon” that prevents access to all except late‐winter mixed‐layer water. Here, we use an eddy‐permitting numerical circulation model to investigate a similar process operating on longer (interannual) timescales in the subpolar North Atlantic. We find that variations in atmospheric forcing are mediated in their translation to the ocean interior, with year‐to‐year changes in the late‐winter mixed layer depth being the critical factor. The signature of persistent strong atmospheric forcing driving deep mixed layers is preferentially ventilated to the interior when the forcing is ceased. Susceptibility to this effect depends on the location and density of subduction—with the rate at which newly ventilated water escapes its region of subduction being the crucial factor.