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Height variation of wind speed and wind distributions statistics
Author(s) -
Justus C. G.,
Mikhail Amir
Publication year - 1976
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl003i005p00261
Subject(s) - wind speed , log wind profile , wind profile power law , weibull distribution , roughness length , wind gradient , meteorology , wind power , power law , probability distribution , environmental science , atmospheric sciences , statistics , mathematics , physics , engineering , electrical engineering
For use in various wind engineering applications (e.g. wind energy conversion, wind loads on structures, air pollution transport) it is desirable to have a consistent relationship by which to project height variations of both "instantaneous" (e.g. few minute average) winds and parameters of the wind speed probability distribution. The power law V 2 /V 1 = (Z 2 /Z 1 ) n is often used for height projection of wind profiles, with the exponent n sometimes taken as depending on surface conditions or on atmospheric stability. The power law profile for wind speed is shown here to be consistent with observed height variation of Weibull wind speed probability distribution functions which have been found to fit observed wind speed distributions (at least above relevant threshold wind speeds). For consistency between the wind speed profiles and the height variation of the Weibull wind speed probability distributions, it is necessary only that the exponent n vary as n = a + b ℓn V 1 , where a and b are constants whose values depend on the reference height at which wind speed V 1 is measured. For a reference height of 10 m, it is found that a = 0.37 and b = −0.0881 (with V 1 in m/s) adequately describes both the observed height variation of wind speed and wind speed probability distributions.