Coupled Ocean–Sea Ice Dynamics of the Antarctic Slope Current Driven by Topographic Eddy Suppression and Sea Ice Momentum Redistribution
Coupled Ocean–Sea Ice Dynamics of the Antarctic Slope Current Driven by Topographic Eddy Suppression and Sea Ice Momentum Redistribution
复制标题
地形涡抑制和海冰动量重新分布驱动的南极坡流耦合海洋-海冰动力学
DOI：
10.1175/jpo-d-21-0142.1
复制
发表时间：
2022
影响因子：
3.5
通讯作者：
Eisenman, Ian
中科院分区：
文献类型：
--
作者：
Si, Yidongfang;Stewart, Andrew L.;Eisenman, Ian
南极斜坡流（ASC）在重新分配水团、海冰和南极边缘周围的示踪剂特性以及调节跨斜坡交换方面起着核心作用。虽然ASC在历史上被理解为风驱动的环流，但最近的研究强调了由于中尺度涡旋和潮汐流而引起的重要动量转移。此外，由于风应力的动量输入是通过海冰转移到ASC在一年中的大部分时间，但以前的研究通常认为独立的海洋和海冰的环流。因此，它仍然不清楚如何从风的动量输入介导的海冰，潮汐强迫，在海洋中的瞬态涡旋，以及如何产生的动量转移结构的ASC。在这项研究中，耦合的海洋-海冰-ASC环流的动力学进行了研究，使用高分辨率的面向过程的模拟和解释与援助的降阶模型。在这里考虑的几乎所有模拟中，海冰重新分配几乎100%的风应力远离大陆坡，导致在ASC的核心在一个完全旋转的平衡状态下，几乎相同的海冰和海洋表面流。这种冰-海耦合是由于大陆坡上空的中尺度涡旋抑制了垂直动量转移，从而使海冰加速海洋表面流动，直到速度一致。潮汐加速的顺坡流夸大了这种影响，甚至可能导致海洋到冰的动量转移。这些研究结果的影响，沿着和跨斜坡运输的水团和南极洲周围的海冰进行了讨论。
The Antarctic Slope Current (ASC) plays a central role in redistributing water masses, sea ice, and tracer properties around the Antarctic margins, and in mediating cross-slope exchanges. While the ASC has historically been understood as a wind-driven circulation, recent studies have highlighted important momentum transfers due to mesoscale eddies and tidal flows. Furthermore, momentum input due to wind stress is transferred through sea ice to the ASC during most of the year, yet previous studies have typically considered the circulations of the ocean and sea ice independently. Thus, it remains unclear how the momentum input from the winds is mediated by sea ice, tidal forcing, and transient eddies in the ocean, and how the resulting momentum transfers serve to structure the ASC. In this study the dynamics of the coupled ocean–sea ice–ASC circulation are investigated using high-resolution process-oriented simulations and interpreted with the aid of a reduced-order model. In almost all simulations considered here, sea ice redistributes almost 100% of the wind stress away from the continental slope, resulting in approximately identical sea ice and ocean surface flows in the core of the ASC in a fully spun-up equilibrium state. This ice–ocean coupling results from suppression of vertical momentum transfer by mesoscale eddies over the continental slope, which allows the sea ice to accelerate the ocean surface flow until the speeds coincide. Tidal acceleration of the along-slope flow exaggerates this effect and may even result in ocean-to-ice momentum transfer. The implications of these findings for along- and across-slope transport of water masses and sea ice around Antarctica are discussed.