Estimation of the global air–sea CO2 gas flux considering wave breaking

We propose a new model with microbreaking and linear dependence on wind speed in the whitecap-free area and linear dependence on the fractional area of whitecaps, based on the whitecap model proposed by Monahan and Spillane (The role of oceanic whitecap in air–sea gas exchange. In: Brutsaert W, Jirka GH (eds) Gas transfer at water surfaces. Reidel, Dordrecht, 495–503, 1984). The relationship between whitecap coverage and wind–sea Reynolds number proposed by Zhao and Toba (J Oceanogr 57:603–616, 2001) provides the link among waves, wind, and whitecap coverage. This model yields a mass transfer velocity that is linear in wind speed at light winds and smoothly transitions with increasing wind to approximately cubic in wind speed and linear in wave age.