The paper estimates air-sea bulk transfer coefficients under diabatic conditions using recent data on sea surface roughness Reynolds number and the Owen-Thomson theory for heat and mass transfer between rough surfaces and the flow above. For a reference height of 10 m, the neutral-lapse transfer coefficient for water vapor is only slightly larger than that for sensible heat. When wind speed at 10 m is greater than 3 m s⁻¹, the sensible heat coefficient (C_H) is about 10% larger than the momentum coefficient (C_D). For wind speeds below 5 m s⁻¹, C_D exceeds C_H, and at 15 m s⁻¹, C_H ≈ 0.8 C_D. The paper proposes ranges for C_D, C_B, and C_H for wind speeds between 4 and 20 m s⁻¹. A plot of diabatic transfer coefficients versus wind speed is obtained using a parameter of sea-air temperature difference. Empirical formulae are suggested for practical use. The paper reviews existing theories on bulk relationships for estimating sensible heat and water vapor transfer between air and sea. However, no conclusive theory has been developed due to incomplete knowledge of the lowest air layer near the sea surface. Recent studies show that the sea surface is aerodynamically rough except in light winds. Heat and mass transfer near rough surfaces are controlled by molecular properties, while momentum is transferred by skin friction and form drag. The difference in transfer mechanisms leads to less increase in heat and mass transfer compared to momentum transfer with surface roughening. In a previous study, Kondo et al. (1973) showed that the representative dimension of sea surface irregularities increases with wind speed. When wind speed exceeds 3 m s⁻¹, this dimension exceeds the laminar sub-layer thickness. The authors proposed that sea surface aerodynamic roughness is related to the roughness Reynolds number, hp u* / v. Based on these results and the assumption that the boundary layer over a solid surface is similar to that over an undulating sea surface, the paper estimates bulk transfer coefficients for sensible heat and water vapor between air and sea. The basic equations for momentum, water vapor, and sensible heat transfer are presented, along with expressions for generalized resistances and bulk transfer coefficients. The paper assumes logarithmic profiles for wind speed, temperature, and humidity in the absence of buoyancy effects.The paper estimates air-sea bulk transfer coefficients under diabatic conditions using recent data on sea surface roughness Reynolds number and the Owen-Thomson theory for heat and mass transfer between rough surfaces and the flow above. For a reference height of 10 m, the neutral-lapse transfer coefficient for water vapor is only slightly larger than that for sensible heat. When wind speed at 10 m is greater than 3 m s⁻¹, the sensible heat coefficient (C_H) is about 10% larger than the momentum coefficient (C_D). For wind speeds below 5 m s⁻¹, C_D exceeds C_H, and at 15 m s⁻¹, C_H ≈ 0.8 C_D. The paper proposes ranges for C_D, C_B, and C_H for wind speeds between 4 and 20 m s⁻¹. A plot of diabatic transfer coefficients versus wind speed is obtained using a parameter of sea-air temperature difference. Empirical formulae are suggested for practical use. The paper reviews existing theories on bulk relationships for estimating sensible heat and water vapor transfer between air and sea. However, no conclusive theory has been developed due to incomplete knowledge of the lowest air layer near the sea surface. Recent studies show that the sea surface is aerodynamically rough except in light winds. Heat and mass transfer near rough surfaces are controlled by molecular properties, while momentum is transferred by skin friction and form drag. The difference in transfer mechanisms leads to less increase in heat and mass transfer compared to momentum transfer with surface roughening. In a previous study, Kondo et al. (1973) showed that the representative dimension of sea surface irregularities increases with wind speed. When wind speed exceeds 3 m s⁻¹, this dimension exceeds the laminar sub-layer thickness. The authors proposed that sea surface aerodynamic roughness is related to the roughness Reynolds number, hp u* / v. Based on these results and the assumption that the boundary layer over a solid surface is similar to that over an undulating sea surface, the paper estimates bulk transfer coefficients for sensible heat and water vapor between air and sea. The basic equations for momentum, water vapor, and sensible heat transfer are presented, along with expressions for generalized resistances and bulk transfer coefficients. The paper assumes logarithmic profiles for wind speed, temperature, and humidity in the absence of buoyancy effects.