Nonlinear vorticity balance of the Antarctic Circumpolar Current
Nonlinear vorticity balance of the Antarctic Circumpolar Current
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DOI：
10.1029/2004jc002753
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发表时间：
2005-11-12
影响因子：
3.6
通讯作者：
Hughes, CW
中科院分区：
文献类型：
--
作者：
Hughes, CW
[1]利用最近公布的全球海洋平均表面动力地形，主要是基于漂流数据，南极绕极流（ACC）的近地表涡度平衡的计算。通过一点平滑，动态地形被发现产生很好的估计，即使是这样的高度分化的相对涡度平流量。在ACC中发现两种明显的流动模式：波长为300 - 500 km的弯曲，其中非线性项很重要，导致相对涡度平流和行星涡度平流之间的平衡，如定常的等正压Rossby波（这意味着表面发散至少部分地被深度处的相反发散所平衡）;以及与地形特征相关的发散流。它是暂时得出结论，这后者流的发散是一个缩放措施的底部压力扭矩。推断的底部压力扭矩显示了大规模的地形相互作用，以及一些尖锐地形特征的强烈影响，例如塔斯曼海以南的断裂带和麦夸里山脊系统以及德雷克海峡的狭窄山脊。
[1] Using a recently published global ocean mean surface dynamic topography, based predominantly on drifter data, the near-surface vorticity balance of the Antarctic Circumpolar Current (ACC) is calculated. With a little smoothing, the dynamic topography is found to produce good estimates of even such highly differentiated quantities as the relative vorticity advection. Two clear modes of flow are found in the ACC: meanders of wavelength 300 - 500 km, in which the nonlinear term is important, resulting in a balance between advection of relative and planetary vorticity, as in a stationary equivalent-barotropic Rossby wave ( this implies a surface divergence which is at least partly balanced by an opposite divergence at depth); and a flow with divergence associated with topographic features. It is tentatively concluded that the divergence of this latter flow is a scaled measure of bottom pressure torque. The inferred bottom pressure torque shows large-scale topographic interactions, as well as a strong influence of some sharp topographic features such as the fracture zones and Macquarie ridge system south of the Tasman Sea, and the narrow ridges in Drake Passage.