Power Spectra and Cospectra for Wind and Scalars in a Disturbed Surface Layer at the Base of an Advective Inversion

McNaughton, K. G.; Laubach, Johannes

doi:10.1023/a:1002477120507

Cited by 50 publications

(59 citation statements)

References 28 publications

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“…In atmospheric boundarylayer studies, the spectra of various turbulence quantities have been thoroughly investigated (Stull, 1988). Examples of spectra from Reynolds shear stress can be found in McNaughton and Laubach (2000). Figure 7 shows P Q (f ) and P u * (f ) (Fig.…”

Section: Spectrum Of Saltation Fluxesmentioning

confidence: 99%

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Turbulent characteristics of saltation and uncertainty of saltation model parameters

et al. 2018

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Abstract. It is widely recognised that saltation is a turbulent process, similar to other transport processes in the atmospheric boundary layer. Due to a lack of high-frequency observations, the statistic behaviour of saltation is so far not well understood. In this study, we use the data from the Japan-Australia Dust Experiment (JADE) to investigate the turbulent characteristics of saltation by analysing the probability density function, energy spectrum and intermittency of saltation fluxes. Threshold friction velocity, u * t , and saltation coefficient, c 0 , are two important parameters in saltation models often assumed to be deterministic. As saltation is turbulent in nature, we argue that it is more reasonable to consider them as parameters obeying certain probability distributions. We estimate these distributions using the JADE data. The factors contributing to the stochasticity of u * t and c 0 are examined.

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Section: Spectrum Of Saltation Fluxesmentioning

confidence: 99%

“…Shao and Mikami (2005) noticed that u * t for 10 min averaged Q and 1 min averaged Q are quite different. Namikas et al (2003) and Ellis et al (2012) have also noticed that averaging intervals of surface shear stress are important to quantifying sediment transport because both shear stress and saltation flux are turbulent.…”

Section: Introductionmentioning

confidence: 99%

Turbulent characteristics of saltation and uncertainty of saltation model parameters

et al. 2018

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“…MoninObukhov similarity theory breaks down (see for instance Kroon and DeBruin, 1995;Bink, 1995 and more recent studies by e.g. McNaughton and Laubach, 2000).…”

Section: Introductionmentioning

confidence: 97%

Regional Advection Perturbations in an Irrigated Desert (RAPID) experiment

Bruin

Hartogensis

Allen

et al. 2004

Theor. Appl. Climatol.

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SummaryThe RAPID field experiment took place in AugustSeptember 1999 at a site 25 km south of Twin Falls, Idaho, USA. The experiment concerned micrometeorological observations over extensive, well-irrigated fields covered with the fast-growing crop alfalfa. During daytime, on a number of days the sensible heat flux was negative and the latent heat flux exceeded net radiation. The energy required for the latent heat flux to be larger than net radiation has to be advected from elsewhere. As the fields were large, we refer to this process as ''regional advection''. ''Local advection'', on the other hand, refers to advection effects, where the wet to dry transition is on a field scale. Evidence is presented that the RAPID data are subject to regional advection conditions.A simple model, based on Penman-Monteith, is derived that describes the regional-advection case rather well. The influence of wind speed under those conditions is illustrated using data and the model. The correlation coefficients between temperature and horizontal wind component appear to be good indicators for advection.

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“…It should be noted that the analysis here does not consider the full range of possibilities known to induce anomalous scaling in FV similarity functions such as advective conditions (Kroon and De Bruin 1995;McNaughton and Laubach 2000;Assouline et al 2008). However, the interplay between outer-layer processes and dissimilarity in canopy scalar sources and sinks, the focus here, remains a logical first step in any basic inquiry on FV similarity functions for carbon dioxide concentration within the CSL.…”

Section: Introductionmentioning

confidence: 99%

On the Anomalous Behaviour of Scalar Flux–Variance Similarity Functions Within the Canopy Sub-layer of a Dense Alpine Forest

Cava

Katul

Sempreviva

et al. 2008

Boundary-Layer Meteorol

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Within the canopy sub-layer (CSL), variability in scalar sources and sinks are known to affect flux-variance (FV) similarity relationships for water vapour (q) and carbon dioxide (C) concentrations, yet large-scale processes may continue to play a significant role. High frequency time series data for temperature (T ), q and C, collected within the CSL of an uneven-aged mixed coniferous forest in Lavarone, Italy, are used to investigate these processes within the context of FV similarity. This dataset suggests that MOST scaling describes the FV similarity function of T even though the observations are collected in the CSL, consistent with other studies. However, the measured FV similarity functions for q and C appear to have higher values than their temperature counterpart. Two hypotheses are proposed to explain the measured anomalous behaviour in the FV similarity functions for q and C when referenced to T . Respired CO 2 from the forest floor leads to large positive excursions in the C time series at the canopy top thereby contributing significantly to both C variance increase and C vertical flux decrease-both leading to an anomalous increase in the FV similarity function. For q, transport of dry air from the outer-layer significantly increases both the variance and the water vapour flux. However, the expected flux increase is much smaller than the variance increase so that the net effect remains an increase in the measured FV similarity function for water vapour above its T counterpart. The hypothesis here is that identifying these events in the temporal and/or in the frequency domain and filtering them from the C and q time series partially recovers a scalar flow field that appears to follow FV similarity theory scaling. Methods for identifying both types of events in the time and frequency domains and their subsequent effects on the FV similarity functions and corollary flow variables, such as the relative transport efficiencies, are also explored.

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Power Spectra and Cospectra for Wind and Scalars in a Disturbed Surface Layer at the Base of an Advective Inversion

Cited by 50 publications

References 28 publications

Turbulent characteristics of saltation and uncertainty of saltation model parameters

Turbulent characteristics of saltation and uncertainty of saltation model parameters

Regional Advection Perturbations in an Irrigated Desert (RAPID) experiment

On the Anomalous Behaviour of Scalar Flux–Variance Similarity Functions Within the Canopy Sub-layer of a Dense Alpine Forest

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