Discovery of an unrecognized pathway carrying overflow waters toward the Faroe Bank Channel
Discovery of an unrecognized pathway carrying overflow waters toward the Faroe Bank Channel
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DOI：
10.1038/s41467-020-17426-8
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发表时间：
2020-07-24
影响因子：
16.6
通讯作者：
Berx, Barbara
中科院分区：
文献类型：
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作者：
Chafik, Leon;Hatun, Hjalmar;Berx, Barbara
北欧海稠密的溢流水域是大西洋经向翻转环流（AMOC）稳定性的一个不可或缺的环节和重要的诊断因素。然而，溢出的途径仍然没有得到很好的解决。在这里，我们使用多个观测平台和涡旋解析海洋模型来识别流向法罗河岸海峡的未被识别的深层水流。我们证明，北欧海的反气旋风力通过其对盆地环流的调节，在激活来自挪威斜坡的一条未被识别的溢流路径方面发挥着关键作用——此时溢流异常强烈。我们进一步确定，无论上游路径如何，溢流大部分是由法罗-设得兰海峡东坡的深层急流携带的，这与之前的想法相反。因此，这条深水流是溢流水通过法罗河岸航道向 AMOC 下游支流供水的主要管道。作者表明，流向法罗河岸海峡的溢流水可能会沿着一条先前未知的路径流向法罗-设得兰海峡，并在那里与位于其东部而不是西部边界的一个未被识别的深层急流汇合。
The dense overflow waters of the Nordic Seas are an integral link and important diagnostic for the stability of the Atlantic Meridional Overturning Circulation (AMOC). The pathways feeding the overflow remain, however, poorly resolved. Here we use multiple observational platforms and an eddy-resolving ocean model to identify an unrecognized deep flow toward the Faroe Bank Channel. We demonstrate that anticyclonic wind forcing in the Nordic Seas via its regulation of the basin circulation plays a key role in activating an unrecognized overflow path from the Norwegian slope - at which times the overflow is anomalously strong. We further establish that, regardless of upstream pathways, the overflows are mostly carried by a deep jet banked against the eastern slope of the Faroe-Shetland Channel, contrary to previous thinking. This deep flow is thus the primary conduit of overflow water feeding the lower branch of the AMOC via the Faroe Bank Channel. The authors show that overflow waters flowing toward the Faroe Bank Channel can take a previously unidentified path to the Faroe-Shetland Channel where it joins an unrecognized deep-reaching jet located along its eastern rather than its western boundary.