Studies in the literature have argued anecdotally that strong near-bottom flow induced by internal tides could transport sediment and modify shelf-edge topography over the long term. To explore this argument, this study quantitatively investigates the topographic influence of internal tides using an idealized quasi-two-dimensional model that represents modern-day conditions at the shelf edge of the Mid-Atlantic Bight off the U.S. northeast coast. Observed temporal evolution of the internal tide amplitude and phases at the Mid-Atlantic Bight shelf edge over a 2-month period is used in conjunction with the model. We i) investigate two sources of semi-diurnal internal tides at the shelf edge, locally generated internal tides (LIT) and incident internal tides (IIT), and ii) consider transport of both suspended and bedload sediment. Model results indicate that LIT alone are inadequate to induce sediment transport, but a combination of tides, LIT and IIT can mobilize sediment at the shelf edge. Modeled sediment transport exhibits a tendency to compensate for changes in shelf-edge curvature and sea level from present-day conditions. However, the present-day shelf-edge profile does not represent a stable condition, as the sediment transport is stronger for the modern configuration than for other hypothetical shelf-edge geometries. Projecting short-term topographic change induced by the combined internal tides over longer timespans (with several major assumptions) indicates that, within the covered parameter range, the shelf-edge seafloor change induced by combined tides and internal tides over 10,000 years has an upper bound of 1–2 m. Sensitivity simulations show that although rates of bed change are affected by bottom roughness, shelf-edge curvature and sea level, the order of magnitude of the seafloor change remains unchanged across the parameter space considered here. This order of magnitude of modeled sediment transport and bed change suggests that it is unlikely for internal tides alone to have significantly shaped the edge of the Mid-Atlantic Bight continental shelf, at least for the conditions considered here. However, whether internal tides have interacted with other oceanographic processes and modified the shelf edge topography and what oceanic processes have shaped the shelf edge topography are questions that remain to be answered.

文献研究指出，长期以来，由内部潮汐引起的强烈的近底流动可以输送沉积物并改变架缘地形。为了探讨这一观点，本研究使用理想化的准二维模型定量研究了内部潮汐的地形影响，该模型代表了美国东北沿海大西洋中部陆架边缘的现代状况。结合该模型，使用了两个月期间大西洋中部海岸线陆架边缘的内部潮汐振幅和相位的时间演变。我们（i）研究架子边缘的半日内潮的两种来源，即局部产生的内潮（LIT）和入射的内潮（IIT），并且ii）考虑悬浮和底质沉积物的运移。模型结果表明，仅靠LIT不足以诱发泥沙输送，但是潮汐，LIT和IIT的组合可以动员架子边缘的泥沙。模拟的泥沙运移表现出一种趋势，可以补偿当今条件下架子边缘曲率和海平面的变化。但是，由于现代构造的泥沙输送比其他假设的架子边缘几何形状要强，因此目前的架子边缘轮廓并不代表稳定的状态。预测由较长时间跨度的内部潮汐组合引起的短期地形变化（有几个主要假设）表明，在覆盖参数范围内，由10,000年以上的合并潮汐和内部潮汐引起的架子边缘海底变化具有上限1-2 m。灵敏度模拟显示，尽管床层变化的速度受底部粗糙度，架子边缘曲率和海平面的影响，但在此处考虑的参数空间中，海床变化的数量级保持不变。模拟的泥沙运移和床层变化的数量级表明，内部潮汐不太可能发生至少在这里考虑的情况下，仅凭此举就可以明显塑造大西洋中部海岸线大陆架的边缘。然而，内部潮汐是否已经与其他海洋学过程相互作用并改变了陆架边缘的地形，以及哪些海洋过程形成了陆架边缘的地形，这是仍有待回答的问题。