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.

中文翻译：

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南大洋通风热点的观测证据

常设曲流是南极环极流 (ACC) 环流系统的关键组成部分，数值研究表明，这些特征可能会在局部增强俯冲、上升流以及横向和垂直示踪剂传输。然而，来自这些地区的观测数据仍然很少。在这里，我们根据一组自主平台对由于极地锋与西南印度洋脊相互作用而形成的 ACC 站立曲流进行采样而得出的测量结果提出了结果。两架海滑翔机被部署在一个生物地球化学-Argo 浮标旁边，该浮标通过立式曲流平流。在站立曲流的高涡动能区域，滑翔机观测显示亚中尺度锋面梯度增强以及深度示踪剂变异性增强，与下游更安静的区域相比。尽管大规模垂直分层相似，但在站立曲流中香料和表观氧气利用的垂直梯度降低，这表明表层海洋的通风更大。这些观察结果与数值研究一致，该数值研究强调了由于中尺度搅拌和亚中尺度垂直速度的增强，站立曲流是通风和俯冲的热点。我们的结果强调需要考虑影响南大洋海气交换、碳输出和生物地球化学循环的过程中的空间异质性。表明表层海洋有更大的通风。这些观察结果与数值研究一致，该数值研究强调了由于中尺度搅拌和亚中尺度垂直速度的增强，站立曲流是通风和俯冲的热点。我们的结果强调需要考虑影响南大洋海气交换、碳输出和生物地球化学循环的过程中的空间异质性。表明表层海洋有更大的通风。这些观察结果与数值研究一致，该数值研究强调了由于中尺度搅拌和亚中尺度垂直速度的增强，站立曲流是通风和俯冲的热点。我们的结果强调需要考虑影响南大洋海气交换、碳输出和生物地球化学循环的过程中的空间异质性。