Role of Future Reef Growth on Morphological Response of Coral Reef Islands to Sea-Level Rise
Role of Future Reef Growth on Morphological Response of Coral Reef Islands to Sea-Level Rise
复制标题
未来珊瑚礁生长对珊瑚礁岛对海平面上升的形态响应的作用
DOI：
10.1002/essoar.10503493.1
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Masselink G
中科院分区：
文献类型：
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作者：
Masselink G
珊瑚礁被广泛认为提供了一个天然的防波堤效果，调节低洼沉积礁岛的侵蚀和洪水危害。由于海平面上升（SLR）导致的珊瑚礁平台水深增加可能会损害这种防波堤效应，并增加岛屿对这些危害的暴露，但SLR引起的珊瑚礁增生可能会对岛屿的恢复力产生积极影响。形态动力学的研究表明，礁岛可以调整SLR保持干舷（岛顶高程以上静水水位）通过过冲沉积和岛屿增生，但不同的未来珊瑚礁增生轨迹的岛屿的形态响应的影响仍然未知。在这里，我们表明，使用基于过程的形态动力学模型，虽然珊瑚礁的生长显着影响波转换过程和岛屿形态，它不会导致减少沿海洪水和岛屿淹没。根据该模型，礁岛演变SLR调整其海拔的最大波浪爬高和岛屿前面的一个不断增长的礁平台达到较低的海拔比那些没有珊瑚礁生长，但有类似的过洗制度。越过岛顶的平均过冲流量Q在岛屿保持SLR和保持干舷的能力方面起着关键作用，Q值为O（10 l m− 1 s −1）将岛屿的建设与破坏分开。因此，如果满足特定的强迫和沉积物供应条件，岛屿可以通过洪水和过洗垂直增长以跟上SLR，为无人居住和人口稀少的岛屿提供希望。然而，岛屿的这种实际应对措施将对发达岛屿的基础设施和资产产生负面影响。
Coral reefs are widely recognized for providing a natural breakwater effect that modulates erosion and flooding hazards on low‐lying sedimentary reef islands. Increased water depth across reef platforms due sea‐level rise (SLR) can compromise this breakwater effect and enhance island exposure to these hazards, but reef accretion in response to SLR may positively contribute to island resilience. Morphodynamic studies suggest that reef islands can adjust to SLR by maintaining freeboard (island crest elevation above still water level) through overwash deposition and island accretion, but the impact of different future reef accretion trajectories on the morphological response of islands remains unknown. Here we show, using a process‐based morphodynamic model, that, although reef growth significantly affects wave transformation processes and island morphology, it does not lead to decreased coastal flooding and island inundation. According to the model, reef islands evolve during SLR by attuning their elevation to the maximum wave runup and islands fronted by a growing reef platform attain lower elevations than those without reef growth, but have similar overwash regimes. The mean overwash dischargeQoveracross the island crest plays a key role in the ability of islands to keep up with SLR and maintain freeboard, with aQovervalue ofO(10 l m−1s−1) separating island construction from destruction. Islands, therefore, can grow vertically to keep up with SLR via flooding and overwash if specific forcing and sediment supply conditions are met, offering hope for uninhabited and sparely populated islands. However, this physical island response will negatively impact infrastructure and assets on developed islands.