Numerical study on effect of tidal phase on storm surge in the South Yellow Sea

Because of the special topography and large tidal range in the South Yellow Sea, the dynamic process of tide and storm surge is very complicated. The shallow water circulation model Advanced Circulation (ADCIRC) was used to simulate the storm surge process during typhoon Winnie, Prapiroon, and Damrey, which represents three types of tracks attacking the South Yellow Sea, which are, moving northward after landing, no landing but active in offshore areas, and landing straightly to the coastline. Numerical experiments were carried out to investigate the effects of tidal phase on the tide-surge interaction as well as storm surge. The results show that the peak surge caused by Winnie and Prapiroon occurs 2-6 h before the high tide and its occurring time relative to high tide has little change with tidal phase variations. On the contrary, under the action of Damrey, the occurring time of the peak surge relative to high tide varies with tidal phase. The variation of tide-surge interaction is about 0.06-0.37 m, and the amplitude variations of interaction are smooth when tidal phase changes for Typhoon Winnie and Prapiroon. While the interaction is about 0.07-0.69 m, and great differences exists among the stations for Typhoon Damrey. It can be concluded that the tide-surge interaction of the former is dominated by the tidal phase modulation, and the time of surge peak is insensitive to the tidal phase variation. While the interaction of the latter is dominated by storm surge modulation due to the water depth varying with tide, the time of surge peak is significantly affected by tidal phase. Therefore, influence of tidal phase on storm surge is related to typhoon tracks which may provide very useful information at the design stage of coastal protection systems.