Wintertime extreme storm waves in the East sea (Japan sea): Numerical experiments of storm wave overtopping in the Fushiki port, the Toyama bay

摘要

In the winter East Sea (ES), storm waves due to winter storms (e.g. extratropical cyclones) under the context of the cold and dry East Asian winter monsoon are frequently reported causing extensive coastal damages along the coasts of Korea and Japan. In February 2008, abnormal storm waves due to a moving low propagating from the west off Hokkaido, Japan, to the south and southwest caused severe coastal damages along the Toyama Bay coast. In this study, we perform numerical experiments on wave overtopping and run-up in the Fushiki Port, Toyama Bay, where the long North-Breakwater was heavily damaged by the storm waves in February 2008. The experiments are conducted using an open-source Gerris flow solver (Gfs) based on modified non-linear shallow-water equation with adaptive mesh refinement (AMR) method and wet-dry scheme for the potential extreme storm waves of 6.78 m and 18.28 sec obtained from statistical analysis and wind wave modeling. The refined mesh efficiently resolves the complicated coastline and coastal structures in the Fushiki Port. The results show that the Fushiki Port would be overtopped and flooded by extreme storm waves if the North-Breakwater does not function properly after being damaged. Also the storm waves would overtop seawalls and sidewalls of the Manyou Pier behind the North-Breakwater. The results also depict that AMR method and wet-dry scheme capture the coastline and coastal structure very well while keeping the computational load efficiently.