Much of the internal tide (IT) is coherent with tidal forcing, but interactions with time-varying ocean flows result in an incoherent component of IT (IIT), which will complicate interpretation of data from the upcoming Surface Water Ocean Topography (SWOT) mission. Here, we demonstrate a simple scheme for estimation of these IIT. We use a short-time harmonic analysis of outputs of a wind- and tidally forced ocean model to generate an ensemble of IT variations in an ocean patch. Principal Components Analysis is used to define the dominant spatial patterns, and combined with sinusoidal time variations at tidal frequencies to define spatio-temporal basis functions that are used to fit sparse altimetry data available in short time windows. The scheme is illustrated using a 1-yr Hybrid Coordinate Ocean Model (HYCOM) run off the Amazon Shelf. Tests with synthetic (SWOT) and real (nadir altimetry) data demonstrate that a significant fraction of IIT can be recovered with this procedure.

中文翻译：

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一种利用测高数据绘制非相干内潮汐的经验制图方法

大部分内部潮汐 (IT) 与潮汐强迫一致，但与随时间变化的海洋流动的相互作用导致 IT (IIT) 的不连贯成分，这将使即将到来的地表水海洋地形 (SWOT) 任务的数据解释复杂化. 在这里，我们展示了一个简单的估计这些 IIT 的方案。我们使用风和潮汐强迫海洋模型输出的短时谐波分析来生成海洋补丁中 IT 变化的集合。主成分分析用于定义主要空间模式，并结合潮汐频率的正弦时间变化来定义时空基函数，用于拟合短时间窗口中可用的稀疏测高数据。该方案使用亚马逊货架外的 1 年混合坐标海洋模型 (HYCOM) 进行说明。