Effect of wind-current interaction on ocean response during Typhoon KAEMI(2006)

The Weather Research and Forecasting(WRF) model,the Princeton Ocean Model(POM),and the wave model(WAVEWATCH III) are used to develop a coupled atmosphere-wave-ocean model,which involves different physical processes including air-forcing,ocean feedback,wave-induced mixing and wave-current interaction.In this paper,typhoon KAEMI(2006) has been examined to investigate the effect of wind-current interaction on ocean response based on the coupled atmosphere-ocean-wave model,i.e.,considering the sea surface currents in the calculation of wind stress.The results show that the wind-current interaction has a noticeable impact on the simulation of 10 m-winds.The model involving the effect of the wind-current interaction can dramatically improve the typhoon prediction.The wind-current interaction prevents excessive momentum fluxes from being transferred into the upper ocean,which contributes to a much smaller turbulence kinetic energy(TKE),vertical diffusivity,and horizontal advection and diffusion.The Sea Surface Temperature(SST) cooling induced by the wind-current interaction during the initial stage of typhoon development is so minor that the typhoon intensity is not very sensitive to it.When the typhoon reaches its peak,its winds can disturb thermocline,and the cold water under the thermocline is pumped up.However,this cooling process is weakened by the wind-current interaction,as ocean feedback delays the decay of the typhoon.Meanwhile,the temperature below the depth of 30 m shows an inertial oscillation with a period about 40 hours(~17°N) when sudden strong winds beat on the ocean.Due to faster currents,the significant wave height decreases as ignoring the wind-current interaction,while this process has a very small effect on the dominant wave length.