Abstract The propagation of tides into coastal aquifers is an important phenomenon in the migration of coastal contaminants, for the representation of shoreline boundary conditions in regional-scale groundwater models, and for the estimation of aquifer properties based on tidal amplitude attenuation and/or phase increase. In this study, an analytical solution to the propagation of tidal fluctuations in a radial flow field, applicable to circular islands, is compared to the existing straight-coastline (“Ferris”) solution. The analytical solution is compared to numerical simulation (using SEAWAT) of a simple-harmonic ocean tide and its propagation within a circular island. This represents the first attempt to combine a previous correction that allows SEAWAT to simulate axisymmetric flow and a modification to SEAWAT to create tidal boundary conditions. Bench testing the analytical solution against the numerical model confirms the numerical approach. The circular-island solution is compared to the Ferris solution in terms of tidal amplitude decay and phase shift. Whereas amplitude decay from the Ferris solution is valid only for near-shore locations within circular islands, the Ferris solution produces reasonable phase lag estimates for typical aquifer diffusivities and for most locations within circular islands. By comparing the Ferris and circular island solutions, we propose a correction factor to the Ferris solution that allows it to be applied in circular boundary settings. This extends the application of the widely applied Ferris solution to a broader range of situations.

中文翻译：

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圆岛潮汐传播解析解的适用性

摘要 潮汐传播到沿海含水层是沿海污染物迁移的重要现象，用于在区域尺度地下水模型中表示海岸线边界条件，以及基于潮汐振幅衰减和/或相位增加估计含水层特性。 . 在这项研究中，将适用于圆形岛屿的径向流场中潮汐波动传播的解析解与现有的直线海岸线（“Ferris”）解进行了比较。将解析解与简单谐波海洋潮汐及其在圆形岛屿内传播的数值模拟（使用 SEAWAT）进行比较。这是首次尝试将先前的修正结合起来，允许 SEAWAT 模拟轴对称流，并修改 SEAWAT 以创建潮汐边界条件。针对数值模型对解析解进行台架测试证实了数值方法。在潮汐振幅衰减和相移方面将圆形岛解与 Ferris 解进行比较。尽管 Ferris 解的幅度衰减仅对圆形岛屿内的近岸位置有效，但 Ferris 解可以为典型的含水层扩散率和圆形岛屿内的大多数位置产生合理的相位滞后估计。通过比较 Ferris 和圆形岛解决方案，我们为 Ferris 解决方案提出了一个修正因子，使其能够应用于圆形边界设置。