Coevolution of Extreme Sea Levels and Sea‐Level Rise Under Global Warming
Coevolution of Extreme Sea Levels and Sea‐Level Rise Under Global Warming
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DOI：
10.1029/2023ef003649
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发表时间：
2023-07
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影响因子：
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通讯作者：
Georgios Boumis;H. Moftakhari;H. Moradkhani
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作者：
Georgios Boumis;H. Moftakhari;H. Moradkhani
海堤、防波堤等海防结构的设计不能再基于平稳性假设。在世界许多地区，由于气候变化导致的预期海平面上升（SLR）将构成不适合未来沿海洪水风险评估的当前极端海平面，因为这将大大增加其发生的可能性。在这里，我们首先表明，全球年最高海平面（AMSLs）在过去几十年中一直在增加，主要是由于平均海平面（MSL）的正变化。然后，我们应用非平稳极值理论，以海平面高度作为协变量来模拟海平面的极端行为，并使用修正的概率海平面上升预估来量化海平面高度在未来几十年的演变。我们的分析表明，与单纯考虑位置参数变化等于MSL上升量的平稳条件相比，非平稳分布表现出明显的差异。通过使用非平稳分布，我们发现，到2050年，在中等（RCP4.5）和高（RCP8.5）代表性浓度路径下，许多地点将经历当前100年的回归水平，其回归周期分别小于15年和9年。此外，我们发现，到本世纪末，即使二氧化碳浓度保持在中等水平（RCP4.5），几乎所有被调查的地点也将达到目前的年100年回报水平。我们的评估通过蒙特卡罗模拟纳入单反预测和非平稳极值分布参数的模糊性来考虑很大的不确定性。
Design of coastal defense structures like seawalls and breakwaters can no longer be based on stationarity assumption. In many parts of the world, an anticipated sea‐level rise (SLR) due to climate change will constitute present‐day extreme sea levels inappropriate for future coastal flood risk assessments since it will significantly increase their probability of occurrence. Here, we first show that global annual maxima sea levels (AMSLs) have been increasing in magnitude over the last decades, primarily due to a positive shift in mean sea level (MSL). Then, we apply non‐stationary extreme value theory to model the extremal behavior of sea levels with MSL as a covariate and quantify the evolution of AMSLs in the following decades using revised probabilistic sea‐level rise projections. Our analysis reveals that non‐stationary distributions exhibit distinct differences compared to simply considering stationary conditions with a change in location parameter equal to the amount of MSL rise. With the use of non‐stationary distributions, we show that by the year 2050 many locations will experience their present‐day 100‐yr return level as an event with return period less than 15 and 9 years under the moderate (RCP4.5) and high (RCP8.5) representative concentration pathways. Also, we find that by the end of this century almost all locations examined will encounter their current 100‐yr return level on an annual basis, even if CO2 concentration is kept at moderate levels (RCP4.5). Our assessment accounts for large uncertainty by incorporating ambiguities in both SLR projections and non‐stationary extreme value distribution parameters via a Monte Carlo simulation.