Abstract Idealized bathymetries were subjected to idealized cyclones in order to measure the storm surge response to a range of shoals, under various storm conditions, for the purpose of informing the development of bathymetry thinning algorithms. Nine bathymetries were considered, including eight large, offshore shoals and a featureless reference domain. Six storm realizations (two different sizes/intensities and three different landfall directions) were used as meteorological forcing. Shoal influence on surge was examined over the entire continental shelf throughout the surge event. Quantification of shoal impact on surge was performed prior to landfall, near the time of peak surge, and during surge recession. Three elevation difference contours (1.0, 0.5, and −0.5 m) were used to quantify the spatial variation in surge caused by the shoals at the three times examined. Positive contours (1.0 and 0.5 m) were used to show that a shoal increased surge locally and the negative contour (−0.5 m) to show that a shoal decreased surge locally. The influences of three shoal parameters (depth below mean sea level (MSL), cross-shore width, and distance from shore) were isolated and examined to see which characteristics caused the shoals to alter surge. In many cases, the shoals did not have much effect on the surge response. Only 13% of the samples used to quantify shoal impact on surge indicated any shoal influence whatsoever, and the shoals did not alter maximum elevation within the threshold considered ( Δ η ≥ | ± 0.5 m | ) anywhere in the domain. However, analysis of the elevation difference contours revealed multiple types of shoal influence. The shoals increased surge when they reduced setdown in storms with offshore winds prior to landfall and when they delayed surge recession after all storms. The shoals decreased surge when they impeded shoreward flow, delaying the arrival of surge. In cases when the shoals altered surge, 95% of the impact was caused by Shallow features (0.5 m below MSL). Also, there appears to be a maximum area over which a shoal can influence surge. All changes in surge greater than the threshold of Δ η ≥ | ± 0.5 m | occurred over the shoal or approximately between the shoal and the shore. The implications of our results for bathymetry thinning follow: In general, offshore shoals do not need to be resolved in bathymetry data sets used in surge modeling, especially if their impact on maximum elevation is the primary concern. Since a shoal's depth below MSL was an excellent indicator of whether it would impact storm surge, we recommend that feature depth below MSL be used as a bathymetry thinning criterion. Finally, a feature's maximum area of influence could be a useful property for determining whether it should be retained in a bathymetry dataset – if one's area of interest is outside of a feature's area of influence, the feature could be omitted regardless of its impact on surge.

中文翻译：

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近海浅滩对风暴潮空间变异性的影响

摘要 理想化的水深受到理想化气旋的影响，以测量在各种风暴条件下对一系列浅滩的风暴潮响应，以便为水深细化算法的开发提供信息。考虑了九个测深，包括八个大型近海浅滩和一个无特征的参考域。六次风暴实现（两种不同的大小/强度和三种不同的登陆方向）被用作气象强迫。在整个浪涌事件中，研究了整个大陆架上的浅滩对浪涌的影响。在登陆前、接近高峰期和浪潮衰退期间对浅滩对浪涌的影响进行了量化。三个高程差等值线（1.0、0.5 和 -0. 5 m) 被用来量化由浅滩引起的 3 次检查的浪涌的空间变化。正等值线（1.0 和 0.5 m）用于表明浅滩局​​部增加了潮汐，负等值线（-0.5 m）表明浅滩局​​部减少了潮汐。三个浅滩参数（低于平均海平面 (MSL) 的深度、跨岸宽度和离岸距离）的影响被隔离和检查，以查看哪些特征导致浅滩改变浪涌。在许多情况下，浅滩对浪涌响应没有太大影响。只有 13% 的用于量化浅滩对涌浪影响的样本表明有任何浅滩影响，并且浅滩没有改变域内任何地方所考虑阈值 (Δ η ≥ | ± 0.5 m | ) 内的最大高程。然而，对高程差等值线的分析揭示了多种类型的浅滩影响。当它们在登陆前用离岸风减少风暴的沉降以及在所有风暴之后延迟潮汐衰退时，这些浅滩增加了潮汐。浅滩在阻碍上岸水流时降低了涌浪，延迟了涌浪的到来。在浅滩改变浪涌的情况下，95% 的影响是由浅层特征（MSL 以下 0.5 m）引起的。此外，似乎有一个浅滩可以影响浪涌的最大区域。大于阈值Δη≥|的所有浪涌变化 ± 0.5 m | 发生在浅滩上或大约在浅滩和海岸之间。我们的结果对测深变薄的影响如下： 一般来说，在用于浪涌建模的测深数据集中不需要解析近海浅滩，特别是如果它们对最大海拔的影响是主要关注点。由于低于 MSL 的浅滩深度是它是否会影响风暴潮的极好指标，我们建议将低于 MSL 的特征深度用作测深变薄标准。最后，要素的最大影响区域可能是确定是否应将其保留在测深数据集中的有用属性——如果一个人感兴趣的区域在要素的影响范围之外，则可以忽略该要素，而不管其对浪涌的影响.