Delayed coastal inundations caused by ocean dynamics post-Hurricane Matthew

Post Hurricane Abnormal Water Level (PHAWL) poses a persistent inundation threat to coastal communities, yet unresolved knowledge gaps exist regarding its spatiotemporal impacts and causal mechanisms. Using a high-resolution coastal model with a set of observations, we find that the PHAWLs are up to 50 cm higher than the normal water levels for several weeks and cause delayed inundations around residential areas of the U.S. Southeast Coast (USSC). Numerical experiments reveal that while atmospheric forcing modulates the coastal PHAWLs, ocean dynamics primarily driven by the Gulf Stream control the mean component and duration of the shelf-scale PHAWLs. Because of the large spatial impact of the post-hurricane oceanic forcing, the coastal hazards are not limited to a direct hit from a hurricane but can be detected throughout the USSC where the oceanic processes reach.

飓风后异常水位（PHAWL）对沿海社区构成持续的淹没威胁，然而关于其时空影响和因果机制仍存在未解决的知识空白。利用一个高分辨率的沿海模型以及一组观测数据，我们发现PHAWL比正常水位在数周内高出多达50厘米，并导致美国东南海岸（USSC）居民区周围出现延迟性淹没。数值实验表明，虽然大气强迫调节沿海的PHAWL，但主要由墨西哥湾流驱动的海洋动力学控制着陆架尺度PHAWL的平均分量和持续时间。由于飓风后海洋强迫的巨大空间影响，沿海灾害并不局限于飓风的直接袭击，而是可以在海洋过程所及的整个美国东南海岸被检测到。