On the wave dependence of sea-surface wind stress - A study by using data from an ocean data buoy station

Analysis is made of wind and wave data, which were obtained during the passage of Typhoon 8013 at an Ocean Data Buoy Station south of Honshu operated by the Japan Meteorological Agency, in order to investigate the wave dependence of sea-surface roughness parameter in the situation where wind waves are dominant with less significant swells. The data fit better the wave-dependent expression of the wind stress, z₀σ_p/u*=γ, than to Charnock's formula, gz₀/u*²=β, where z₀ is the roughness length, σ_p the angular frequency of the spectral peak of wind waves, u* the friction velocity of air, g the acceleration of gravity, γ and β are non-dimensional constants. The results are very similar to those of our previous study using data from an oil producing platform in the Bass Strait, Australia, although the type of observation system and the synoptic situation of the winds and wind waves were totally different.