Observational Evidence of Ventilation Hotspots in the Southern Ocean
Observational Evidence of Ventilation Hotspots in the Southern Ocean
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DOI：
10.1029/2021jc017178
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发表时间：
2021-07-01
影响因子：
3.6
通讯作者：
Gary, Alison R.
中科院分区：
文献类型：
--
作者：
Dove, Lilian A.;Thompson, Andrew F.;Gary, Alison R.
常设曲流是南极绕极流（ACC）环流系统的一个关键组成部分，数值研究表明，这些功能可能会局部增强俯冲，上升流，以及横向和垂直示踪剂输送。然而，来自这些地区的观测数据仍然很少。在这里，我们提出的结果的基础上进行的测量由一组自主平台采样的ACC常设曲流形成由于极锋与西南印度洋脊的相互作用。两个海上滑翔机被部署在一个生物地球化学-阿尔戈漂浮物旁边，该漂浮物被平流输送通过站立的曲流。在高涡动动能区的常设曲流，滑翔机的观测显示增强的次中尺度锋面梯度以及提高示踪剂的变化在深度，相比更安静的区域进一步下游。香料的垂直梯度和明显的氧气利用率降低，尽管在大规模的垂直分层的相似性，表明更大的通风的表面海洋的常设曲流。这些意见是一致的数值研究，突出常设蜿蜒作为热点的通风和俯冲，由于增强中尺度搅拌和亚中尺度垂直速度。我们的研究结果强调，需要考虑空间异质性的影响海气交换过程中，碳输出，在南大洋和地球化学循环。
Standing meanders are a key component of the Antarctic Circumpolar Current (ACC) circulation system, and numerical studies have shown that these features may locally enhance subduction, upwelling, as well as lateral and vertical tracer transport. Yet, observational data from these regions remain sparse. Here, we present results based on measurements made by a group of autonomous platforms sampling an ACC standing meander formed due to the interaction of the Polar Front with the Southwest Indian Ridge. Two Seagliders were deployed alongside a Biogeochemical-Argo float that was advected through the standing meander. In the high eddy kinetic energy region of the standing meander, the glider observations reveal enhanced submesoscale frontal gradients as well as heightened tracer variability at depth, as compared to the more quiescent region further downstream. Vertical gradients in spice and apparent oxygen utilization are reduced in the standing meander despite similarities in the large-scale vertical stratification, suggesting greater ventilation of the surface ocean. These observations are consistent with numerical studies that highlight standing meanders as hotspots for ventilation and subduction due to enhanced mesoscale stirring and submesoscale vertical velocities. Our results emphasize the need to account for spatial heterogeneity in processes influencing air-sea exchange, carbon export, and biogeochemical cycling in the Southern Ocean.