Energy analysis of wind-induced wave and current during typhoon kalmaegi

The mechanism of energy transfer from the atmosphere to the ocean remains poorly characterized, and models used to drive wave and circulation based on the total energy input from the atmosphere to the ocean therefore require further validation. To this end, we identify the typhoon-induced energy input process by eliminating the influence of background field, tide and boundary. The reliability of the model results is verified by observations made in the South China Sea (SCS) during Typhoon Kalmaegi (2014). As expected, we find that the transfer of wind energy to waves is the main component of energy input to the ocean as a whole. The wind energy input to the wave reaches a maximum when the wave direction is the same as the wind direction, with a maximum value of 28.51 W/m2 during the typhoon. With wave growth, the energy is transferred from the high to low frequency in the wave spectrum. These findings allow us to consider the wind energy input to the ocean as a parametric expression, and we propose a correction scheme for the drag coefficient of the wave model, which can be assimilated into actual forecast operations.