๐”– Bobbio Scriptorium
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Vertical cross-spectra of horizontal velocity components at the Boulder observatory

โœ Scribed by Rick Soucy; Robert Woodward; H. A. Panofsky

Publisher
Springer
Year
1982
Tongue
English
Weight
555 KB
Volume
24
Category
Article
ISSN
0006-8314

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โœฆ Synopsis

Cross-spectra between horizontal wind components at different levels ofthe Boulder Atmospheric Observatory (BAO) tower lead to the following conclusions:

(1) Davenport's hypothesis is satisfied that coherence decays exponentially with the ratio of vertical separation to horizontal wave length, at least to very small values of coherence.

(2) The decay coefficients increase with z/L for z/L < 0.5. For larger stabilities, irregular fluctuations with periods of order lo-20 min have considerable vertical coherence. Results at BAO are quite consistent with those elsewhere.

(3) Eddy slopes in vertical planes increase with wind shear up to a point where the slope (horizontal delay over vertical separation) is just above 2. Beyond that point, the systematic increase of slopes with shear ceases. Since wind shear decreases upward, slopes tend to decrease upward. Slopes for lateral components are significantly larger than those for u-components.

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## Abstract Power spectra of horizontal wind components at 91 m indicate the existence of a gap near wavelengths of the order of 10 km or periods of the order of one hour.