The generation and subsequent evolution of nonlinear internal waves (NLIWs) in the Strait of Georgia (British Columbia, Canada) is investigated with both remote sensing images and a three-dimensional regional non-hydrostatic numerical simulation. Many satellite images depict clear snapshots of two successive NLIWs propagating northward about 1 h or 4 km apart during the flood tides. In the model results, local energy budget analysis demonstrates that the generation processes of internal waves are dominated by the energy conversion from barotropic tides to internal tides, while propagation processes are dominated by high-frequency NLIWs after radiating away the Boundary Pass. To further investigate the generation mechanisms of local internal waves, sensitivity studies with different tidal forcing are carried out. In the standard spring tide experiment, the rank-order NLIW packets have relatively large leading waves (∼15 m amplitude) and small trailing waves radiating from the Boundary Pass, related to a complex evolution of an internal Froude number over the sill. The internal Froude number analysis also demonstrates that only when the diurnal (D1) and semidiurnal (D2) tides act in phase can paired NLIW packets be formed. However, either single D1 or D2 tides, or D1 and D2 tides not in phase, are not able to generate NLIWs, as condition of the flow remain subcritical at all times. Moreover, a series of sensitivity experiments demonstrate that the role of non-hydrostatic mode is crucial in the high-resolution model but less important in the coarse-resolution model, via comparing wave properties and wave energetics in non-hydrostatic and hydrostatic models.

乔治亚海峡（加拿大不列颠哥伦比亚省）非线性内波 (NLIW) 的产生和随后的演化通过遥感图像和三维区域非流体静力数值模拟进行了研究。许多卫星图像描绘了两个连续的 NLIW 的清晰快照，它们在涨潮期间向北传播，相距约 1 小时或 4 公里。在模型结果中，局部能量收支分析表明，内波的产生过程以正压潮汐向内潮汐的能量转换为主，而传播过程则以辐射出边界通道后的高频 NLIW 为主。为了进一步研究局部内波的产生机制，开展了不同潮汐强迫的敏感性研究。在标准的大潮实验中，等级顺序 NLIW 包具有相对较大的前波（~15 m 振幅）和从边界通道辐射的小尾波，与基台上内部弗劳德数的复杂演化有关。内部弗劳德数分析也表明，只有当日潮（D1）和半日潮（D2）同相作用时，才能形成成对的 NLIW 包。然而，无论是单个 D1 或 D2 潮汐，还是不同相位的 D1 和 D2 潮汐，都无法产生 NLIW，因为水流条件始终保持亚临界状态。此外，一系列灵敏度实验表明，通过比较非流体静力和流体静力模型中的波浪特性和波浪能量，非流体静力模式的作用在高分辨率模型中至关重要，但在粗分辨率模型中不太重要。