Significance of diapycnal mixing within the Atlantic Meridional Overturning Circulation
Significance of diapycnal mixing within the Atlantic Meridional Overturning Circulation
复制标题
大西洋经向翻转环流中二重混合的意义
DOI：
10.1002/essoar.10512257.1
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Cimoli L
中科院分区：
文献类型：
--
作者：
Cimoli L
海底混合形成了气候上重要的示踪剂的分布，如热量和碳，因为它们是由海洋内部密集的水团携带的。在这里，我们分析了一套基于观测的周期混合估计，以评估其在大西洋经向翻转环流（AMOC）中的作用。大西洋内部的水质量转变速率表明北大西洋深水（NADW，中性密度γ N≃27.6-28.15）在48°N - 32°S之间具有0.5-8 Sv的周期环流，浮力显著增加。此外，向南流动的NADW内的示踪剂可能会经历大量的纵向转移，相当于垂直方向上数百米的垂直位移。AMOC的纬向平均数值模型证实了这一结果，表明混合可以改变示踪剂在南大洋的上行位置，最终影响其全球路径和通风时间尺度。这些结果表明，为了理解和可靠地预测正在进行的气候变化，需要在气候模式中有一个现实的混合表示。
Diapycnal mixing shapes the distribution of climatically important tracers, such as heat and carbon, as these are carried by dense water masses in the ocean interior. Here, we analyze a suite of observation‐based estimates of diapycnal mixing to assess its role within the Atlantic Meridional Overturning Circulation (AMOC). The rate of water mass transformation in the Atlantic Ocean's interior shows that there is a robust buoyancy increase in the North Atlantic Deep Water (NADW, neutral densityγn≃ 27.6–28.15), with a diapycnal circulation of 0.5–8 Sv between 48°N and 32°S in the Atlantic Ocean. Moreover, tracers within the southward‐flowing NADW may undergo a substantial diapycnal transfer, equivalent to a vertical displacement of hundreds of meters in the vertical. This result, confirmed with a zonally averaged numerical model of the AMOC, indicates that mixing can alter where tracers upwell in the Southern Ocean, ultimately affecting their global pathways and ventilation timescales. These results point to the need for a realistic mixing representation in climate models in order to understand and credibly project the ongoing climate change.