The internal tide (IT) is the internal wave with tidal frequency. During propagation, ITs are scattered by topographies such as seamounts and slopes. Mesoscale eddies, which generally consist of anticyclonic eddies (AEs) and cyclonic eddies (CEs), are widely observed in the ocean and can modulate scattering processes. However, whether AEs and CEs affect topographic scattering of IT differently is unknown. In this study, the responses of semidiurnal IT scattering to mesoscale eddies are explored based on LLC4320 data and idealized numerical simulations. The results suggest that mesoscale eddies can both enhance and weaken scattering in topographic regions, causing spatial divergence in the scattering in response to eddies. This modulation can be attributed to the refraction of mode one IT by mesoscale eddies. AEs and CEs refract IT to opposite directions; therefore, they have opposite effects on modulating topographic scattering. Regions that undergo amplification of scattering by an AE would probably experience the weakening of scattering caused by a CE. These findings imply that eddies can actively participate in modulating IT scattering, which contributes to a better understanding of the interaction between internal waves and mesoscale eddies.

中文翻译：

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隐藏在中尺度涡旋之下的内潮散射的演化


内潮（IT）是具有潮汐频率的内波。在传播过程中，IT 会因海山和斜坡等地形而分散。中尺度涡流通常由反气旋涡流（AE）和气旋涡流（CE）组成，在海洋中广泛观察到，可以调节散射过程。然而，AE 和 CE 是否对 IT 的地形散射产生不同的影响尚不清楚。在本研究中，基于 LLC4320 数据和理想化数值模拟，探讨了半日 IT 散射对中尺度涡流的响应。结果表明，中尺度涡流既可以增强也可以减弱地形区域的散射，从而导致响应涡流的散射的空间发散。这种调制可归因于中尺度涡流对模式一 IT 的折射。 AE 和 CE 将 IT 折射到相反的方向；因此，它们对调制地形散射具有相反的作用。经历 AE 散射放大的区域可能会经历 CE 引起的散射减弱。这些发现意味着涡流可以积极参与调制IT散射，这有助于更好地理解内波和中尺度涡流之间的相互作用。