The Influence Of Momentum And Energy Regulation Of Surface Waves On The Upper Ocean Flow Field Under High Wind Speed

The evolution of surface gravity waves strongly modulates momentum and energy transfers across the air-sea interface and ultimately affects the size and direction of ocean currents.Consequently,studying the influence of how surface waves govern momentum and energy on the laminar current field is of great significance with regards to physical processes occurring at the air-sea interface and upper ocean dynamics.Joint usage of WAVEWATCH III simulated and IBTr ACS tropical cyclone data are used to explore the influence of surface gravity waves on the transmission of momentum and energy from the atmosphere to the ocean.In addition,a combination of subsurface current field data observed by drifters and Wind Sat radiometer wind field data is used to characterize the modulation of momentum and energy by surface waves on the upper ocean current field under high wind speed conditions.In seas governed by storm track in winter,results show that differences in momentum(?_diff)and energy(EF_diff)across the air-sea interface are relatively large and according to a global distribution if inverse wave age,it is found that younger waves can absorb more momentum and energy from the atmosphere under high wind speed conditions.Combined with tropical cyclone data,it is determined that the greater a cyclone's intensity and translation speed,the larger ?_diff and EF_diff are.Due to the asymmetric distribution of wind and wave fields on both sides of tropical cyclones,the distribution of?_diff andEF_diff is also asymmetric.Larger values of ?_diff occur behind the tropical cyclone's translation direction.Maximum values of EF_diff is distributed in the right rear quadrant.It is concluded that the greater the wind speed,the smaller the angle between the wind direction and the wave direction and thus,the greater the regulating effect of surface waves on momentum and energy.At high wind speeds,the ratio of current speed to wind speed is between 1%and 2%.The currents in the northern hemisphere tend to propagate to the right side of the wind direction,and the currents in the southern hemisphere tend to the left side of the wind direction.Based on the effect of surface waves on the upper ocean currents field at high wind speeds,the velocity calculated without considering the effect of surface waves on momentum regulation is on average about 6%higher than the observed velocity.Irrespective of the Stokes drift caused by nonlinear waves,the size of the subsurface currents field will be underestimated by 3%-10%.Stokes drift has the greatest impact when the wind speed is about 30m/s.