ABSTRACT

We focused on the effects of tides on storm surge deviations. According to previous studies, storm surge deviations depend on when the typhoon strikes in the tidal phase because the water depth of a bay varies with tides. The previous studies concluded that the dependence can be explained by the conventional formula. However, the results of our numerical simulations could not be explained quantitatively by the conventional formula and require a development mechanism for storm surges that are not expressed in the formula, to explain the dependency. Therefore, we focused on the water depth gradient, and confirmed from the numerical simulation results that the depth gradient greatly influenced the development characteristics of storm surges. Moreover, a new formula considering the depth gradient was derived, and the tidal dependence of storm surge deviations was investigated. Based on the new formula, two indexes that indicate the effect of the water depth gradient and the effect of tides on storm surges were derived. We examined the indexes to clearly understand the development characteristics of storm surges. Finally, the validity of the derived indexes was investigated by comparing the computed surge heights based on the indexes with the results of the numerical simulations.

摘要

我们专注于潮汐对风暴潮偏差的影响。根据先前的研究，风暴潮的偏差取决于台风在潮汐阶段的袭击时间，因为海湾的水深随潮汐而变化。先前的研究得出结论，依赖性可以用常规公式来解释。然而，我们的数值模拟结果无法通过常规公式进行定量解释，需要公式中未表达的风暴潮的发展机制来解释相关性。因此，我们重点研究了水深梯度，并从数值模拟结果证实了水深梯度对风暴潮的发展特征有很大影响。此外，推导出了一个考虑深度梯度的新公式，并对风暴潮偏差的潮汐依赖性进行了研究。根据新公式，推导出指示水深梯度影响和潮汐对风暴潮影响的两个指标。通过对指标的考察，清楚地了解风暴潮的发展特征。最后，通过将基于这些指标计算出的浪涌高度与数值模拟结果进行比较，考察了导出指标的有效性。