Probability density functions of turbulent velocity and temperature in the atmospheric surface layer

Chu, Chia Ren; Parlange, Marc B.; Katul, Gabriel G.; Albertson, J. D.

doi:10.1029/96wr00287

Cited by 82 publications

(87 citation statements)

References 28 publications

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“…For very stable conditions, σ u /u * increases strongly. This behaviour has also been observed by other researchers (Smedman, 1988;De Bruin et al, 1993;Chu et al, 1996;Hsieh and Katul, 1997). For strongly stable stratification the turbulent motion is damped (u * becomes small) and for increasing ζ the stabilizing effect dominates.…”

Section: Turbulence Statisticssupporting

confidence: 86%

“…Whereas only few published data sets for the u and v components exist, results for the w component can be found frequently in the literature (e.g., Merry and Panofsky, 1976;Kondo et al, 1978;Nieuwstadt, 1984a;Smedman 1988;De Bruin et al, 1993;Chu et al, 1996;Mahrt et al, 1998). Even though the scaling behaviour of the w component seems to be relatively well known, uncertainties still exist under strong atmospheric stability.…”

Section: Turbulence Statisticsmentioning

confidence: 99%

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On Monin–Obukhov Similarity In The Stable Atmospheric Boundary Layer

Pahlow

Parlange

Porté‐Agel

2001

Boundary-Layer Meteorology

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Abstract. Atmospheric measurements from several field experiments have been combined to develop a better understanding of the turbulence structure of the stable atmospheric boundary layer. Fast response wind velocity and temperature data have been recorded using 3-dimensional sonic anemometers, placed at several heights (≈1 m to 4.3 m) above the ground. The measurements were used to calculate the standard deviations of the three components of the wind velocity, temperature, turbulent kinetic energy (TKE) dissipation and temperature variance dissipation. These data were normalized and plotted according to Monin-Obukhov similarity theory. The non-dimensional turbulence statistics have been computed, in part, to investigate the general applicability of the concept of z-less stratification for stable conditions. From the analysis of a data set covering almost five orders of magnitude in the stability parameter ζ = z/L (from near-neutral to very stable atmospheric stability), it was found that this concept does not hold in general. It was only for the non-dimensional standard deviation of temperature and the average dissipation rate of turbulent kinetic energy that zless behaviour has been found. The other variables studied here (non-dimensional standard deviations of u, v, and w velocity components and dissipation of temperature variance) did not follow the concept of z-less stratification for the very stable atmospheric boundary layer. An imbalance between production and dissipation of TKE was found for the near-neutral limit approached from the stable regime, which matches with previous results for near-neutral stability approached from the unstable regime.

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Section: Turbulence Statisticssupporting

confidence: 86%

Section: Turbulence Statisticsmentioning

confidence: 99%

On Monin–Obukhov Similarity In The Stable Atmospheric Boundary Layer

Pahlow

Parlange

Porté‐Agel

2001

Boundary-Layer Meteorology

Self Cite

219

150

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“…Two different types of idealized vegetation are examined in conjunction [5] with the gravel roughness (D 70 =10 mm), i.e., idealized grass formed using artificial grass (Astroturf) and rigid vegetation arranged in a staggered grid formed from plastic ( Figure 1). The vegetation and gravel form patches of width 0.307 m and length 1.825 m and alternate in a checkerboard formation down the channel [6,7].…”

Section: Vegetation Types and Roughness Generationmentioning

confidence: 99%

Probability Distribution of Turbulent Velocity Fluctuations in a Patchy Vegetated Open Channel

Folorunso¹

2017

J Civil Environ Eng

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The probability density function (PDF) for the stream wise velocity fluctuations was obtained for various cross sections in a patchy vegetated open channel. The pdf obtained for all the cross sections appeared to be qualitatively Gaussian, hence adequate to predict the extreme values arising from coherent structures of the patchy vegetated open channel for two experimental conditions. Relative to gravel bed, it is shown that the vegetation stem density produces asymmetric velocity fluctuations over the vegetated bed due to more distortion of large scale flow structures. At the boundary region however, the pdf is negatively skewed in experiment two relative to experiment one. This asymmetry is attributed to the enhanced lateral transport of momentum at the boundary region.

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“…We assume that the longitudinal and lateral velocity components of short-term fluctuations are Gaussian distributed (as in a neutral boundary layer, Chu et al 1996). This corresponds to the assumption that higher than second-order moments are zero in Eq.…”

Section: Monte Carlo Experimentsmentioning

confidence: 99%

Impact of wind gusts on sea surface height in storm surge modelling, application to the North Sea

Grinten

Vries

Swart³

2012

Nat Hazards

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Storm surge models usually do not take into account the explicit effect of wind gusts on the sea surface height. However, as the wind speed enters quadratically into the shallow water equations, short-term fluctuations around the mean value do not average out. We investigate the impact of explicitly added gustiness on storm surge forecasts in the North Sea, using the WAQUA/DCSM model. The sensitivity of the model results to gustiness is tested with Monte Carlo simulations, and these are used to derive a parametrisation of the effect of gustiness on characteristics of storm surges. With the parametrisation and input from the ECMWF model archive, we run hindcasts for a few individual cases and also the 2007-2008 winter storm season. Although the explicit inclusion of gustiness increases the surge levels, it does not help to explain, and hence reduce, the errors in the model results. Moreover, the errors made by ignoring gustiness are small compared to other errors. We conclude that, at present, there is no need to include gustiness explicitly in storm surge calculations for the North Sea.

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Probability density functions of turbulent velocity and temperature in the atmospheric surface layer

Cited by 82 publications

References 28 publications

On Monin–Obukhov Similarity In The Stable Atmospheric Boundary Layer

On Monin–Obukhov Similarity In The Stable Atmospheric Boundary Layer

Probability Distribution of Turbulent Velocity Fluctuations in a Patchy Vegetated Open Channel

Impact of wind gusts on sea surface height in storm surge modelling, application to the North Sea

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