The Effect of Non‐Stationarity on Extreme Sea‐Level Estimation
The Effect of Non‐Stationarity on Extreme Sea‐Level Estimation
复制标题
非平稳性对极端海平面估计的影响
DOI：
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复制
发表时间：
1999
期刊：
影响因子：
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通讯作者：
J. Tawn
中科院分区：
文献类型：
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作者：
M. Dixon;J. Tawn
海平面是天文潮汐和气象涌动过程的组成部分。由于平均水平的长期趋势、确定性潮汐分量、潮汐季节性以及潮汐与潮汐之间的相互作用的组合，它表现出时间非平稳性。我们评估了这些非平稳性对极端海平面分布估计的影响。这对于沿海洪水评估非常重要，因为传统的分析方法假设，一旦趋势被消除，极端海平面就来自平稳序列。我们将传统方法与最近提出的替代方案进行了比较，该替代方案结合了潮汐成分及其相关相互作用的知识，并将其应用于 22 个英国数据站点并通过模拟研究。我们的主要发现是，如果忽略潮汐非平稳性，那么大多数地点的极端海平面都会被大大低估。相比之下，如果不对潮汐季节性和潮汐-潮汐相互作用进行建模，则传统方法几乎不会产生额外偏差。人们发现替代方法表现良好，但需要更多的统计建模和更好的数据质量。
The sea‐level is the composition of astronomical tidal and meteorological surge processes. It exhibits temporal non‐stationarity due to a combination of long‐term trend in the mean level, the deterministic tidal component, surge seasonality and interactions between the tide and surge. We assess the effect of these non‐stationarities on the estimation of the distribution of extreme sea‐levels. This is important for coastal flood assessment as the traditional method of analysis assumes that, once the trend has been removed, extreme sea‐levels are from a stationary sequence. We compare the traditional approach with a recently proposed alternative that incorporates the knowledge of the tidal component and its associated interactions, by applying them to 22 UK data sites and through a simulation study. Our main finding is that if the tidal non‐stationarity is ignored then a substantial underestimation of extreme sea‐levels results for most sites. In contrast, if surge seasonality and the tide–surge interaction are not modelled the traditional approach produces little additional bias. The alternative method is found to perform well but requires substantially more statistical modelling and better data quality.