Existing empirical relations for gas transfer velocity at wind-wave interface are expressed in terms of wind speed only, and so the difference in their estimated values may be caused by wave parameters such as wave age. A new model of transfer velocity describing the effects of wave breaking is formulated on the basis of the hybrid models of Woolf (2005) and Soloviev et al. (2007). The model expression and the values of parameters are examined in comparison with existing empirical relations. The present model can estimate wave-dependent gas transfer velocities and shows that wind-speed dependence in empirical relations is probably based on wave age. Also, the present model may be used to describe the behaviors of laboratory data with wave age.
2016 Japan Society of Civil Engineers