Evaluation of air-sea bulk formula

Eddy-correlation fluxes are compared to air-sea fluxes predicted by a widely used bulk flux formulation without wave state effects. Systematic discrepancies are found. For example, the model approximately equates the roughness lengths for heat and moisture, however, with weak to moderate wind speeds, the observed roughness length for heat exceeds that for moisture by an order of magnitude or more. This is apparently due to the dynamic nature of temperature, which dominates buoyancy generation of turbulence in these datasets. For wind speeds above a threshold value, the roughness length for moisture exceeds that for heat apparently due to enhanced moisture flux associated with the onset of wave breaking coupled with advection of cold dry air from land. In near-collapsed turbulence, the observed momentum flux is smaller than predicted, and there is no clear indication of a smooth flow viscous regime.