The Simulation of a Storm Surge and Wave due to Typhoon Sarah using an Integrally Coupled Tide-surge-wave Model of the Yellow and East China Seas

Abstract

The Yellow and East China Seas are characterized byshallow shelf seas, seasonal monsoons and typhoons, especiallythe Korean Peninsula’s western coastal area, which features largetides, a complex coastline and many islands. This study implementedan integrally coupled tide-surge-wave model based on an unstructuredgrid to evaluate the impact of Typhoon Sarah, which occurred inSeptember of 1959, on the Yellow and East China Seas and, specifically,the southern coast of Korea in terms of waves and storm surges.The model results projected a significant wave height of 2–7 m, amean wave period of 4–14 sec, and positive surge heights that were0.3–1 m along the southern coast of Korea. Additional model runsincluded two independent model runs for waves and tides, and onetide-surge model run was conducted to investigate the interactionsin the wave, tide and storm surge processes. The coupled tide-surgewavemodel reasonably reproduced wave properties and stormsurges, but uncoupled models, i.e. independent models, slightlyoverestimated waves and surges. The wave forces associated withthe gradient radiation stress resulted in water being elevated intocoastal regions, thereby the water elevation increased onshore andthe reverse happened offshore. A possible water level change dueto a storm equivalent to Typhoon Sarah in the year 2100 wasestimated by considering a mean sea level rise of 70 cm and wasgenerally in the range of 70–100 cm in the Yellow and East ChinaSeas and approximately 68 cm along the southern coast of Korea.