Near-Inertial Energy Propagation inside a Mediterranean Anticyclonic Eddy
Near-Inertial Energy Propagation inside a Mediterranean Anticyclonic Eddy
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DOI：
10.1175/jpo-d-19-0211.1
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发表时间：
2020-08
影响因子：
3.5
通讯作者：
M. Lelong;Y. Cuypers;P. Bouruet-Aubertot
中科院分区：
文献类型：
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作者：
M. Lelong;Y. Cuypers;P. Bouruet-Aubertot
受 2010 年从寡营养到超寡营养地中海生物地球化学 (BOUM) 实验期间对半永久反气旋塞浦路斯涡底部强烈近惯性波信号观察的启发，进行了一项数值研究，以研究近惯性/涡旋相互作用在混合层能量转移中的作用。使用混合时空分解将所有变量分成三个独立的分量：慢速（涡流）和快速（惯性振荡+波），这对于理解流动动力学很有用。通过详细的能量收支分析，我们发现反气旋涡流在将风驱动的惯性能量转移到传播波方面起着催化剂的作用。虽然涡流设定了波浪的空间尺度，但它不参与任何能量交换。通过涡流核心的近惯性传播导致形成多个临界水平，其中在涡流底部波能的最大积累。补充射线追踪分析揭示了当表面限制惯性射线源自负涡度区域时临界水平的形成。相反，源自该区域之外的射线聚焦在涡流底部，并且可以在深度处传播。
Motivated by observations of a strong near-inertial wave signal at the base of the semipermanent anticyclonic Cyprus Eddy during the 2010 Biogeochemistry from the Oligotrophic to the Ultraoligotrophic Mediterranean (BOUM) experiment, a numerical study is performed to investigate the role of near-inertial/eddy interactions in energy transfer out of the mixed layer. A hybrid temporal–spatial decomposition is used to split all variables into three independent components: slow (eddy) and fast (inertial oscillations + waves), which proves useful in understanding the flow dynamics. Through a detailed energy budget analysis, we find that the anticyclonic eddy acts as a catalyst in transferring wind-driven inertial energy to propagating waves. While the eddy sets the spatial scales of the waves, it does not participate in any energy exchange. Near-inertial propagation through the eddy core results in the formation of multiple critical levels with the largest accumulation of wave energy at the base of the eddy. A complementary ray-tracing analysis reveals critical-level formation when the surface-confined inertial rays originate within the negative vorticity region. In contrast, rays originating outside this region focus at the base of the eddy and can propagate at depth.