Role of Residual Overturning for the Sensitivity of Southern Ocean Isopycnal Slopes to Changes in Wind Forcing
Role of Residual Overturning for the Sensitivity of Southern Ocean Isopycnal Slopes to Changes in Wind Forcing
复制标题
残余倾覆对南大洋等密度斜坡对风强迫变化敏感性的影响
DOI：
10.1175/jpo-d-19-0072.1
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发表时间：
2019
影响因子：
3.5
通讯作者：
R. Ferrari
中科院分区：
文献类型：
--
作者：
Madeleine K. Youngs;G. Flierl;R. Ferrari
南极绕极流在全球海洋的热量和碳的流通中发挥着核心作用。特别是，等重斜率决定了每个水团露头的位置，从而决定了海洋如何与大气相互作用。区域积分等重斜率被认为是涡流饱和的，即随着风力变化而保持相对恒定，但在现实的当前和未来参数状态下，流是否饱和是未知的。本研究分析了一个理想化的两层准地转通道模型，该模型由风应力和两层之间界面上的质量通量产生的残余倾覆所驱动，有或没有阻塞脊。剩余倾覆的符号和强度设定为等重坡度随风力而变化，遵循通常的惯例，导致正倾覆随着风力的增加坡度增大，负倾覆的坡度减小；这种行为是由于风应力减弱时主导的直立曲流减弱造成的，导致等重坡度对风应力的变化变得更加敏感，并与平底模拟的坡度收敛。只有当风力超过临界水平时，涡流饱和才会出现。这些结果表明，饱和度理论必须同时考虑地形和残余倾覆，才能完整，并为理解南大洋等密度坡度如何响应未来风力变化而变化提供框架。
The Antarctic Circumpolar Current plays a central role in the ventilation of heat and carbon in the global ocean. In particular, the isopycnal slopes determine where each water mass outcrops and thus how the ocean interacts with the atmosphere. The region-integrated isopycnal slopes have been suggested to be eddy saturated, that is, stay relatively constant as the wind forcing changes, but whether or not the flow is saturated in realistic present day and future parameter regimes is unknown. This study analyzes an idealized two-layer quasigeostrophic channel model forced by a wind stress and a residual overturning generated by a mass flux across the interface between the two layers, with and without a blocking ridge. The sign and strength of the residual overturning set which way the isopycnal slopes change with the wind forcing, leading to an increase in slope with an increase in wind forcing for a positive overturning and a decrease in slope for a negative overturning, following the usual conventions; this behavior is caused by the dominant standing meander weakening as the wind stress weakens causing the isopycnal slopes to become more sensitive to changes in the wind stress and converge with the slopes of a flat-bottomed simulation. Eddy saturation only appears once the wind forcing passes a critical level. These results show that theories for saturation must have both topography and residual overturning in order to be complete and provide a framework for understanding how the isopycnal slopes in the Southern Ocean may change in response to future changes in wind forcing.
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影响因子：
3.5
作者：
A. Thompson;A. N. Garabato
通讯作者：
A. Thompson;A. N. Garabato
影响因子：
3.5
作者：
Howard E
通讯作者：
Howard E
DOI：
10.5194/tc-13-3093-2019
发表时间：
2019-05
期刊：
The Cryosphere
影响因子：
--
作者：
M. Cooper;Thomas M. Jordan;D. M. Schroeder;M. J. Siegert;Christopher N. Williams;J. Bamber
通讯作者：
M. Cooper;Thomas M. Jordan;D. M. Schroeder;M. J. Siegert;Christopher N. Williams;J. Bamber
DOI：
10.48550/arxiv.1610.00621
发表时间：
2016
期刊：
--
影响因子：
--
作者：
Mak J
通讯作者：
Mak J