High Wind and Power Density Over Global Oceans

Spacebased scatterometer measures ocean surface roughness, which is in equilibrium with surface stress (momentum flux). Under general conditions, the variation of stress is reflected in the variation of winds. Eight years of QuikSCAT data are used to give a good representation of the probability distribution and power density of wind speed over global oceans and to provide useful applications. For hurricane-scale winds (> 35 m/s), present scatterometer measurements are not sensitive to increase in winds. Although strong efforts have been made to adjust the model functions for retrieving winds under moderate wind to the strong wind conditions and to improve the sensor design to retrieve strong winds, such effort is likely to be limited by the natural process of turbulent transport. Surface stress does not increase with wind in hurricane-scale winds due to flow separation.