Importance of Mesoscale Currents in AMOC Pathways and Timescales
Importance of Mesoscale Currents in AMOC Pathways and Timescales
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中尺度电流在 AMOC 路径和时间尺度中的重要性
DOI：
10.1175/jpo-d-21-0244.1
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发表时间：
2022
影响因子：
3.5
通讯作者：
Garraffo, Zulema
中科院分区：
文献类型：
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作者：
Kamenkovich, Igor;Garraffo, Zulema
大西洋经向翻转环流（AMOC）由于吸收和重新分配热量和碳异常而在气候中起着关键作用。这种重新分布沿着连接高纬度北大西洋与中纬度和南大洋的几条主要路径进行，涉及到各种空间尺度的海流。本数值研究探讨中尺度电流（“涡”）在这些AMOC路径和相关的时间尺度的重要性，使用一个高效的离线示踪剂模式。该研究使用了两个边界脉冲响应（BIR）示踪剂，可以量化大西洋示踪剂交换的重要性与高纬度大气在北方和南大洋在南方。结果表明，中尺度平流导致增加的整体BIR库存在第一个100年，并导致更有效的和空间均匀的通风深大西洋。中尺度流也促进BIR示踪剂的纬向传播，从而有助于大尺度平流。结果表明，空间不均匀性和各向异性的涡流诱导混合在几个混合的“热点”，所揭示的涡流扩散张量的重要性。可以预期的结论，以协助评估涡允许的模拟，停止短的中尺度的全分辨率，以及涡参数化方案的发展。
The Atlantic Meridional Overturning Circulation (AMOC) plays a key role in climate due to uptake and redistribution of heat and carbon anomalies. This redistribution takes place along several main pathways that link the high-latitude North Atlantic with mid-latitudes and the Southern Ocean and involves currents on a wide range of spatial scales. This numerical study examines the importance of mesoscale currents (“eddies”) in these AMOC pathways and associated timescales, using a highly efficient offline tracer model. The study uses two Boundary Impulse Response (BIR) tracers, which can quantify the importance of the Atlantic tracer exchanges with the high-latitude atmosphere in the north and with the Southern Ocean in the south. The results demonstrate that mesoscale advection leads to an increase in the overall BIR inventory during the first 100 years and results in a more efficient and spatially uniform ventilation of the deep Atlantic. Mesoscale currents also facilitate meridional spreading of the BIR tracer and thus assist the large-scale advection. The results point toward the importance of spatial inhomogeneity and anisotropy of the eddy-induced mixing in several mixing “hot spots”, as revealed by an eddy diffusivity tensor. Conclusions can be expected to assist evaluations of eddy-permitting simulations, that stop short of full resolution of mesoscale, as well as development of eddy parameterization schemes.