A recently proposed model of foam impact on the air–sea drag coefficient Cd has been employed for the estimation of the effective foam-bubble radius Rb variation with wind speed U10 in hurricane conditions. The model relates Cd(U10) with the effective roughness length Zeff(U10) represented as a sum of aerodynamic roughness lengths of the foam-free and foam-covered sea surfaces Zw(U10) and Zf(U10) weighted with the foam coverage coefficient αf(U10). This relation is treated for known phenomenological distributions Cd(U10), Zw(U10), and αf(U10) at strong wind speeds as an inverse problem for the effective roughness parameter of foam-covered sea surface Zf(U10). The present study is aimed at the estimation of the effective roughness of the sea surface assuming that the measurement data for the effective drag coefficient are known. The effective foam-bubble size is found as a function of the wind speed.
- Drag reduction
- Ocean-atmosphere exchange
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