Turbulence characteristics along several towers

Observations from several towers are used to show how measurements of wind and temperature near the surface can be used to estimate the variances of the horizontal velocity and the dissipation rate up to the top of the towers, provided the roughness length is known. The roughness length usually varies with wind direction, and the traditional methods of estimating it tend to lead to over-estimates.Analysis of cross spectra between velocity components at different levels shows that Davenport's Geometrical Similarity is satisfied. Coherence falls off exponentially with the ratio of height interval to wavelength, and the ‘decay parameter’ depends on Richardson number near the surface. Coherences at different sites show no significant differences in neutral air. The lateral velocity components have larger coherence and more time delay between levels than the horizontal components at all sites.Time delay and coherence are also discussed in other Cartesian directions, and it is suggested that these quantities, having relatively simple properties, can be used as building blocks for an empirical three-dimensional model of turbulence.

[1]  Hans A. Panofsky,et al.  Recent spectra of atmospheric turbulence , 1968 .

[2]  Hans A. Panofsky,et al.  Scale analysis of atmospheric turbulence at 2 m , 1962 .

[3]  I. A. Singer,et al.  Vertical structure of turbulence , 1965 .

[4]  Rj Taylor.  Thermal Structures in the Lowest Layers of the Atmosphere , 1958 .

[5]  Hans A. Panofsky,et al.  Determination of stress from wind and temperature measurements , 1963 .

[6]  Hans A. Panofsky,et al.  Change of terrain roughness and the wind profile , 1964 .

[7]  W. Swinbank.  The exponential wind profile , 1964 .

[8]  d Structures,et al.  Wind effects on buildings and structures : proceedings [of the] International Research Seminar, Ottawa, Canada, 11-15 September 1967 , 1968 .

[9]  J. Deardorff,et al.  Dependence of air‐sea transfer coefficients on bulk stability , 1968 .

[10]  A. Davenport.  The spectrum of horizontal gustiness near the ground in high winds , 1961 .

[11]  M. Barad,et al.  PROJECT PRAIRIE GRASS, A FIELD PROGRAM IN DIFFUSION. VOLUME II , 1958 .

[12]  A. K. Blackadar,et al.  Investigation of the turbulent wind field below 150-meter altitude at the eastern test range , 1969 .

[13]  J. Pandolfo,et al.  Wind and Temperature Profiles for Constant-flux Boundary Layers in Lapse Conditions with a Variable Eddy Conductivity to Eddy Viscosity Ratio , 1966 .

[14]  John L. Lumley,et al.  The structure of atmospheric turbulence , 1964 .

[15]  I. A. Singer,et al.  RELATION OF GUSTINESS TO OTHER METEOROLOGICAL PARAMETERS , 1953 .