The Dependence of Boundary-Layer Shear on Diurnal Variation of Stability

Heald, R. C.; Mahrt, L.

doi:10.1175/1520-0450(1981)020<0859:tdobls>2.0.co;2

Cited by 14 publications

(15 citation statements)

References 3 publications

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“…This will require statistical dynamic stability-dependent analysis, which is able to deal e.g., with occasional (but not necessarily regular) occurrence of low-level wind maxima. Relevant earlier research was undertaken by Buajitti and Blackadar (1957), Haltiner (1961) and Matveev (1967), and more recently e.g., by Clarke (1974) and Heald and Mahrt (1981). Unless we understand these phenomena quantitatively, we cannot link surface wind climate to macroscale climate.…”

Section: Discussionmentioning

confidence: 99%

Shapes of annual frequency distributions of wind speed observed on high meteorological masts

Wieringa

1989

Boundary-Layer Meteorol

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Annual wind distributions from six masts are used to investigate the annual variability of hourly-average wind. A variability extremum occurs at the height where the average diurnal cycle of wind reverses its phase from a nocturnal minimum to a nocturnal maximum. A simple profile model shows that in non-complex terrain, this reversal height varies approximately between 50 m at coasts and 90 m inland. The Weibull distribution shape factor k has a maximum at the reversal height, and with decreasing height, k decreases approximately as a linear function of height. Therefore estimation of wind distribution shape from surface data is possible in the surface layer. In the upper PBL, however, such estimation is not very feasible, because no simple methods are available to estimate the reversal height from routine surface observations.

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Section: Discussionmentioning

confidence: 99%

Shapes of annual frequency distributions of wind speed observed on high meteorological masts

Wieringa

1989

Boundary-Layer Meteorol

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“…This is consistent with the heights chosen by other investigators such as Heald and Mahrt (1981). Obviously, it is questionable to apply the atmospheric conditions estimated for this layer to much higher levels.…”

Section: Discussionmentioning

confidence: 99%

“…Figure 6 shows the results for mean wind shear. A similar presentation was made by Heald and Mahrt (1981) for the data at two layers (7-55 and 56-123 m), obtained from an instrumented tower in Rise, Denmark. Their results correspond to Figure 6 for the case of all undisturbed winds (II).…”

Section: Discussionmentioning

confidence: 99%

“…Most obviously, the fatigue of rotors and the power output of generators are affected by mean and fluctuating wind shear. While there have been several studies of mean wind shear (e.g., Frost etal., 1978;Sisterson and Frenzen, 1978;Heald and Mahrt, 1981) and fluctuating shear (e.g., Fichtl, 1971 and1972;Ramsdell, 1978;Doran, 1981), investigations of wind shear associated with conditions disturbed by frontal passages and other events related to storms are relatively rare. The present investigation compares frontal (disturbed) with nonfrontal (undisturbed) wind shears.…”

Section: Introductionmentioning

confidence: 99%

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A comparison of wind speed shears for frontal and undisturbed synoptic conditions

Sheih

1984

Boundary-Layer Meteorol

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Wind speed shear parameters derived from data collected at a 481-m TV tower are computed for disturbed conditions (cold frontal passage), all undisturbed winds, undisturbed high winds, and undisturbed low winds. The exponential values ofthe wind speed power law for the case of disturbed conditions are found to be smaller than those for the case of all undisturbed winds, for practically all atmospheric stabilities; the largest exponential value (0.45) appears in the undisturbed low wind case at Richardson numbers near 0.25. The largest mean and standard deviations of the wind shear at the lowest layer (7-26 m) arc 0.129 and 0.066 s ', respectively, which occur for the high wind case at near-neutral stability. The most significant differences between the cases of disturbed and all undisturbed winds are that the former has much larger wind speeds and wind shear standard deviations in atmospherically-stable conditions.

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“…However, an earlier comparison between SWT and tetroon trajectories (200-400 m above mean sea level) during night hours showed a variation of wind direction shear with height that was opposite to that exsistent with the recent evaluation of boundary layer shear on the diurnal variations of atmospheric stability. 11 Substitution of Eq. 3 into Eq.…”

Section: K -mentioning

confidence: 99%