Dependence of sea surface drag coefficient on wind-wave parameters

The relationships between sea surface roughness z₀ and wind-wave parameters are analyzed, andspurious self-correlations are found in all of the parameterization schemes. Sea surface drag coeffi-cient C_D is fitted by four wind-wave parameters that are wave age, wave steepness, windsea Reynoldsnumber R_B and R_H, and the analyzed data are divided into laboratory, field and combined datasets respectively. Comparison and analysis of dependence of C_D on wind-wave parameters showthat R_B can fit the C_D most appropriately. Wave age and wave steepness are not suitable to fit C_Dwith a narrow range data set. When the value of wave age has a board range, R_H is not suitableto fit C_D either. Three relationships between C_D and R_B are integrated into the bulk algorithmCOARE to calculate the observational friction velocity, and the results show that the relationshipbetween C_D and R_B which is fitted with field data set can describe the momentum transfer in theopen ocean, under low-moderate wind speed condition, most appropriately.