Abstract Hot spots of sea level variability along the North American East Coast have been shown to shift in latitude repeatedly over the past 95 years and connections with a number of forcing phenomena, including the North Atlantic Oscillation (NAO) and Atlantic Meridional Overturning Circulation (AMOC), have been suggested. Using a barotropic 1/12° NEMO model of the North American East Coast (to represent the upper ocean and a homogeneous shelf), we investigate the coastal sea level response to remote sea surface height (SSH) variability along the upper continental slope. Hilbert transform Complex EOF analysis is used to investigate the responses to interannual changes in the strength of the mean winds and an idealised NAO. Variability in the mean winds produces in-phase coastal sea level variability along the entire coastline and is driven by a SSH anomaly in the subpolar gyre. Variability due to the NAO forcing is in phase along the coast south of Cape Hatteras. Interannual coastal sea level variability at a given latitude is found to be driven by off-shore SSH anomalies originating many degrees of latitude ( ∼ 100s km) further north, and linear barotropic trapped wave theory is used to explain the mechanism. A comparison of the results from an analytical model with those from the numerical model is used to suggest that the boundary wave mechanism is also relevant for understanding the coastal response to interior sea level change over longer time periods. Nonlinear effects are found not to significantly modify the character of the linear solution.

中文翻译：

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北美东海岸近海强迫海平面热点和边界波的理想化建模

摘要 在过去的 95 年中，北美东海岸海平面变化的热点已被证明在纬度上反复变化，并与许多强迫现象有关，包括北大西洋涛动 (NAO) 和大西洋经向翻转环流 (AMOC) )，已被建议。使用北美东海岸的正压 1/12° NEMO 模型（代表上层海洋和同质大陆架），我们研究了沿海海平面对沿上大陆坡的远程海面高度 (SSH) 变化的响应。希尔伯特变换 复合 EOF 分析用于研究对平均风强度和理想化 NAO 的年际变化的响应。平均风的变化在整个海岸线上产生同相沿海海平面变化，并由次极地环流中的 SSH 异常驱动。由 NAO 强迫引起的变化在哈特拉斯角以南的海岸同相。发现给定纬度的年际沿海海平面变化是由源自更北许多纬度（~100s km）的离岸 SSH 异常驱动的，并且线性正压陷波理论被用来解释该机制。将分析模型的结果与数值模型的结果进行比较，表明边界波机制也与了解沿海对较长时间段内海平面变化的响应有关。发现非线性效应不会显着改变线性解决方案的特征。