A Mechanism of Turbulent Transfer in the Atmospheric Surface Layer

[摘要] Micro-meteorological data are analysed to determine the flux-gradient relationships for the tamsfer of momentum, sensible heat and water vapor in the atmospheric surface layer. The results obtained agree well with the universal relationships under the condition of (Ζ/L) varying from 0 to -1 for the unstable and from 0 to 0.25 for the stable. The universal relationships imply a relationship between eddy diffusivity and the stability parameter Ζ/L. The derivation shows that the gradient Richardson number Ri is not equal to the Ζ/L. Empirical evidence for the validity is obtained.A turbulent-scale, which is derived in this report, is related to the eddy diffusivities. The results show that the eddy diffusivities for momentum, sensible heat and water vapor are expressedrespectively by KM=ε1/3Lυ4/3 KH=ε1/3Lu1/3•Lθ Kωε1/3Lυ1/3LwHere, Li indicates the turbulent-scale in the vertical direction of wind, temperature and water vapor respectively with a subscript of υ, θ and ω. ε is the dissipation rate of turbulent energy.

[学科分类] 大气科学