Abstract
The application of Taylor's hypothesis to atmospheric boundary layer turbulence at heights of 15, 30 and 58 m has been investigated by correlation analysis and phase-spectral analysis of data taken from lines of meteorological towers when the mean wind direction was essentially along the tower line. The time lag of maximum cross correlation between parallel components measured at different alongwind locations indicates that the eddy structure travels slightly faster than the mean value of the longitudinal wind at the same height. The autocorrelation functions in space and in time for the longitudinal and vertical components show good agreement, as predicted by Talyor's hypothesis, for space lags up to 252 m. The agreement for the lateral component is inferior for lags ≥32 m.
According to Lin, Taylor's hypothesis holds in boundary layer shear flow for those wavenumbers κ such that κŪ≫dŪ/dz. Phase spectral analysis of parallel wind component data at different alongwind locations shows Taylor's hypothesis to hold for κŪ≥4dŪ/dz for near-neutral turbulence.
Preliminary coherency analysis of the same data indicates that the coherency (not squared) for parallel components falls to a value of less than e−1 for wavelengths less than three-halves the separation distance between measuring points.
