Impacts of the Ocean Surface Velocity on Wind Stress Coefficient and Wind Stress over Global Ocean during 1958-2001

By accounting for the effects of ocean surface velocity (wave-induced surface drift velocity and current velocity) on the drag coefficient, the spatial distribution of drag coefficient and wind stress are computed over the global ocean during 1958-2001, using an empirical drag coefficient parameterization formula based on wave steepness and wind speed. The global ocean current field is generated from the Hybrid Coordinate Ocean Model (HYCOM) and the waves from Wavewatch III (WW3). The spatial and temporal variability of the drag coefficient and wind stress are analyzed. Preliminary results indicate that, the ocean surface drift velocity exerts an influence on the drag coefficient, about 5% in average. The results also show that accounting for the effect of the ocean surface velocity on the wind stress can lead to significant improvement in the modeling of ocean circulation and air-sea interaction processes.