Abstract Internal waves such as those produced by tidal sloshing over seafloor topography play an important role in the energy budget of the oceanic overturning circulation. Understanding their spatial and temporal structure, which depend on both the details of the forcing topography and the forcing frequency, is relevant in predicting how and where wave breaking and mixing may occur. Past work has largely focused on the case of a monochromatic wave field; however, the forcing tides may be composed of multiple frequency constituents. Here we present an approach by which the vertical mode structure of a polychromatic internal wave field may be computed from velocity timeseries data without any a priori knowledge of the details of the forcing topography. We consider wave fields in both uniform and vertically-varying stratification, and show using synthetic data that our approach is able to accurately reconstruct the vertical mode strengths. The sensitivity of our approach to noise and vertical resolution is also examined.

中文翻译：

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任意分层多色内波场的模态分解

摘要 潮汐晃动在海底地形产生的内波在海洋翻转环流的能量收支中起着重要作用。了解它们的空间和时间结构，这取决于强迫地形和强迫频率的细节，与预测波浪破碎和混合可能发生的方式和地点有关。过去的工作主要集中在单色波场的情况上。然而，强迫潮汐可能由多个频率成分组成。在这里，我们提出了一种方法，通过该方法可以从速度时间序列数据计算多色内波场的垂直模式结构，而无需任何关于强迫地形细节的先验知识。我们考虑均匀分层和垂直变化分层中的波场，并使用合成数据表明我们的方法能够准确地重建垂直模式强度。还检查了我们的方法对噪声和垂直分辨率的敏感性。