Interaction of Superinertial Waves with Submesoscale Cyclonic Filaments in the North Wall of the Gulf Stream
Interaction of Superinertial Waves with Submesoscale Cyclonic Filaments in the North Wall of the Gulf Stream
复制标题
超惯性波与湾流北壁亚中尺度气旋细丝的相互作用
DOI：
10.1175/jpo-d-17-0079.1
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发表时间：
2018
影响因子：
3.5
通讯作者：
D’Asaro, Eric A.
中科院分区：
文献类型：
--
作者：
Whitt, Daniel B.;Thomas, Leif N.;Klymak, Jody M.;Lee, Craig M.;D’Asaro, Eric A.
在墨西哥湾流北壁进行的高分辨率、近拉格朗日速度和密度观测揭示了近惯性波（NIWs）的带状剪切结构特征。在这里，气流遵循亚中尺度动力学，罗斯比和理查德森数接近1，垂直涡度为正。这允许对NIWs与亚中尺度气流的相互作用进行独特的分析，这些气流以气旋涡旋为主，而不是反气旋涡旋。旋转光谱显示，垂直剪切矢量在接近和高于局部科里奥利频率f的频率上，主要随深度和时间顺时针旋转。在某些深度，超过一半的测量剪切变化可以用频率在1.7f之间的顺时针旋转运动来解释。主导的超惯性频率与从亚中尺度流中NIWs的频散关系推断的频率一致，该频散关系取决于观测到的波切变长径比以及平衡流的垂直涡度、斜压性和分层。这些观测激发了对北壁超惯性波传播的射线追踪计算，在那里，强气旋涡度的多个细丝强烈地改变了波的传播。计算结果表明，惯性-重力波的最小允许频率大多大于科里奥利频率，超惯性波可以在旋流涡旋丝之间的斜向临界层被捕获和放大，这为观测到的剪切方差主要由超惯性波主导提供了新的合理解释。
High-resolution, nearly Lagrangian observations of velocity and density made in the North Wall of the Gulf Stream reveal banded shear structures characteristic of near-inertial waves (NIWs). Here, the current follows submesoscale dynamics, with Rossby and Richardson numbers near one, and the vertical vorticity is positive. This allows for a unique analysis of the interaction of NIWs with a submesoscale current dominated by cyclonic as opposed to anticyclonic vorticity. Rotary spectra reveal that the vertical shear vector rotates primarily clockwise with depth and with time at frequencies near and above the local Coriolis frequencyf. At some depths, more than half of the measured shear variance is explained by clockwise rotary motions with frequencies betweenfand 1.7f. The dominant superinertial frequencies are consistent with those inferred from a dispersion relation for NIWs in submesoscale currents that depends on the observed aspect ratio of the wave shear as well as the vertical vorticity, baroclinicity, and stratification of the balanced flow. These observations motivate a ray tracing calculation of superinertial wave propagation in the North Wall, where multiple filaments of strong cyclonic vorticity strongly modify wave propagation. The calculation shows that the minimum permissible frequency for inertia–gravity waves is mostly greater than the Coriolis frequency, and superinertial waves can be trapped and amplified at slantwise critical layers between cyclonic vortex filaments, providing a new plausible explanation for why the observed shear variance is dominated by superinertial waves.
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影响因子：
3.5
作者：
L. Thomas;Craig M. Lee;Y. Yoshikawa
通讯作者：
L. Thomas;Craig M. Lee;Y. Yoshikawa
影响因子：
--
作者：
E. Pallàs‐Sanz;J. Candela;J. Sheinbaum;J. Ochoa;J. Jouanno
通讯作者：
E. Pallàs‐Sanz;J. Candela;J. Sheinbaum;J. Ochoa;J. Jouanno
影响因子：
3.7
作者：
Eric Danioux;J. Vanneste;P. Klein;H. Sasaki
通讯作者：
Eric Danioux;J. Vanneste;P. Klein;H. Sasaki
沿海上升流区域内潮与锋区的相互作用
DOI：
--
发表时间：
1969
期刊：
影响因子：
--
作者：
C. Mooers
通讯作者：
C. Mooers
JASIN (1978) 实验期间在混合层中观测到的近惯性运动与局部风应力和准地转流场的关系
DOI：
--
发表时间：
1982
期刊：
影响因子：
--
作者：
R. Weller
通讯作者：
R. Weller