Dependence of sea surface drag coefficient on wind-wave parameters

The relationships between sea surface roughness z0 and wind-wave parameters are analyzed, and spurious self-correlations are found in all of the parameterization schemes. Sea surface drag coefficient CD is fitted by four wind-wave parameters that are wave age, wave steepness, windsea Reynolds number RB and RH, and the analyzed data are divided into laboratory, field and combined data sets respectively. Comparison and analysis of dependence of CD on wind-wave parameters show that RB can fit the CD most appropriately. Wave age and wave steepness are not suitable to fit CD with a narrow range data set. When the value of wave age has a board range, RH is not suitable to fit CD either. Three relationships between CD and RB are integrated into the bulk algorithm COARE to calculate the observational friction velocity, and the results show that the relationship between CD and RB which is fitted with field data set can describe the momentum transfer in the open ocean, under low-moderate wind speed condition, most appropriately.