Research On Wave Current Interaction Under Strong Sea Conditions

Waves and ocean currents are the two most important and the most common dynamic processes in the oceans,which are independent of and at the same time influence each other.And the interaction between them has a great effect on many oceanographic phenomena,such as storm surges,rip currents,nearshore circulation and the sea surface temperature,so it is practically important to carry out further research.Until now,such study is mainly on wave-current interaction about nearshore breaking waves.However,the northwest Pacific is the area which is influenced by tropical cyclones seriously,so it is important to study wave-current interaction in serious sea conditions in northwest Pacific,which will help to improve the forecast accuracy in such case.In this paper,study is carried out about wave-current interaction during the influence of No.1 Super Typhoon Nepartak and No.14 Super Typhoon Meranti in2016.SWAN model,ROMS model and SWAN-ROMS coupling model are used respectively to study the influence of wave-current interaction on significant wave height.Conclusions can be obtained:(1)The influence the significant wave height of wave-current interaction is mainly affected by angle between wave direction and sea surface current direction:when the wave and the current have much the same direction on the right track of typhoons,wave-current interaction will decrease the significant wave height;in those areas where the wave and the current have the opposite direction,wave-current interaction will increase the significant wave height high;the closer the angle between the wave and the current is to 90°,the less influence wave-current interaction has on the significant wave height;in those areas far from the typhoon center,wave-current interaction is weak because of slow sea current;on the whole,the significant wave heights when using SWAN-ROMS coupling model are more close to the actual observation data.(2)Interaction of wave-current is more obvious in nearshore areas and thoseareas along continental shelves possibly,indicating that the geography has a great effect on wave-induced currents.(3)Considering the interaction of wave and current,the simulation level of sea surface temperature can be improved.The interaction of wave and current enhance the vertical mixing in the ocean upper layer,and increases the amplitude of SST changes before and after the typhoon.This phenomenon is more obvious in nearshore areas;On the right track of typhoons,the direction of wind,current and wave is almost same,which will cause more cool water to rise to the surface,the area the low temperature is more wide.