Structure–Function Parameters in the Convective Boundary Layer from Large-Eddy Simulation

Peltier, L. J.; Wyngaard, J. C.

doi:10.1175/1520-0469(1995)052<3641:spitcb>2.0.co;2

Cited by 38 publications

(39 citation statements)

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“…C 2 T decreases in the mixed layer up to levels where entrainment processes become important, leading to temperature fluctuations at the interface between the mixed layer and free atmosphere and thus a secondary peak in C 2 T . The shape of the C 2 T profiles is in agreement with previous LES studies (Peltier and Wyngaard 1995;Cheinet and Siebesma 2009;Maronga et al 2013b) and semi-empirical profiles after Kaimal et al (1976). The shape of C 2 q is in agreement with previous studies as well (Fairall 1987;Peltier and Wyngaard 1995;Cheinet and Cumin 2011;Maronga et al 2013b).…”

Section: Mean Profilessupporting

confidence: 91%

“…The grid was stretched in the vertical direction well above the top of the ABL in the free atmosphere to save computational time. MOST was applied as a surface boundary condition locally between the surface and the first computational grid level ("local similarity model", see also Peltier and Wyngaard 1995), including the calculation of the local friction velocity u * . A 1.5-order flux-gradient subgrid closure scheme after Deardorff (1980) was applied (see also Moeng and Wyngaard 1988;Saiki et al 2000), which requires the solution of an additional prognostic equation for the subgrid-scale (SGS) turbulent kinetic energy.…”

Section: Les Modelmentioning

confidence: 99%

“…While Wyngaard and LeMone (1980) suggested A q ≈ 1.5, Andreas (1991) proposed that A T = A q = 2.7 (when R T q = 1), referring to the study of Hill (1989). The previous LES study of Peltier and Wyngaard (1995) suggested A q = 2.0−2.7. However, these authors also showed that A q can be higher than A T due to entrainment effects.…”

Section: Monin-obukhov Similarity Relationshipsmentioning

confidence: 99%

“…Unlike in situ measurements, where the (heterogeneous) surface fluxes are basically unknown, they can be explicitly prescribed in the LES model. Previous LES studies have shown that vertical profiles and local estimates of C 2 T and C 2 q can be reliably derived from LES data for the homogeneously-heated CBL (Peltier and Wyngaard 1995;Cheinet and Siebesma 2009;Cheinet and Cumin 2011;Wilson and Fedorovich 2012;Maronga et al 2013b). Cheinet and Siebesma (2009) studied the spatial variability of C 2 T and found a bimodal log-normal distribution in the lower boundary layer, which was previously also found in the Sodar measurements of Petenko and Shurygin (1999).…”

Section: Introductionmentioning

confidence: 97%

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The Effect of Surface Heterogeneity on the Structure Parameters of Temperature and Specific Humidity: A Large-Eddy Simulation Case Study for the LITFASS-2003 Experiment

Maronga

Hartogensis

Raasch

et al. 2014

Boundary-Layer Meteorol

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We conduct a high-resolution large-eddy simulation (LES) case study in order to investigate the effects of surface heterogeneity on the (local) structure parameters of potential temperature C 2 T and specific humidity C 2 q in the convective boundary layer (CBL). The kilometre-scale heterogeneous land-use distribution as observed during the LITFASS-2003 experiment was prescribed at the surface of the LES model in order to simulate a realistic CBL development from the early morning until early afternoon. The surface patches are irregularly distributed and represent different land-use types that exhibit different roughness conditions as well as near-surface fluxes of sensible and latent heat. In the analysis, particular attention is given to the Monin-Obukhov similarity theory (MOST) relationships and local free convection (LFC) scaling for structure parameters in the surface layer, relating C 2 T and C 2 q to the surface fluxes of sensible and latent heat, respectively. Moreover we study possible effects of surface heterogeneity on scintillometer measurements that are usually performed in the surface layer. The LES data show that the local structure parameters reflect the surface heterogeneity pattern up to heights of 100-200 m. The assumption of a blending height, i.e. the height above the surface where the surface heterogeneity pattern is no longer visible in the structure parameters, is studied by means of a two-dimensional correlation analysis. We show that no such blending height is found at typical heights of scintillometer measurements for the studied case. Moreover, C 2 q does not follow MOST, which is ascribed to the entrainment of dry air at the top of the boundary layer. The application of MOST and LFC scaling to elevated C 2 T data still gives reliable estimates of the surface sensible heat flux. We show, however, that this flux, derived from scintillometer data, is only representative of the footprint area of the scintillometer, whose size depends strongly on the synoptic conditions.

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Section: Mean Profilessupporting

confidence: 91%

Section: Les Modelmentioning

confidence: 99%

Section: Monin-obukhov Similarity Relationshipsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

See 2 more Smart Citations

The Effect of Surface Heterogeneity on the Structure Parameters of Temperature and Specific Humidity: A Large-Eddy Simulation Case Study for the LITFASS-2003 Experiment

Maronga

Hartogensis

Raasch

et al. 2014

Boundary-Layer Meteorol

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“…This structure function can be related to the structure function of the temperature, the humidity and their joint structure parameter (see [32]). However, we will consider the humidity effects negligible.…”

Section: Atmospheric Seeing Parametersmentioning

confidence: 99%

Variational Multiscale based dissipation models for the estimation of atmospheric seeing

Baiges

Codina

2015

Computers & Fluids

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In this work we present a numerical model for the estimation of atmospheric seeing in observation sites. The particularity of the method is that it is based on a Variational MultiScale turbulence model, its main feature being that the numerical mechanisms which are used to deal with stability issues (convection and the inf-sup condition for incompressible flows) do also take care of the modeling of turbulence. Based on this turbulence model, we develop the expressions for the viscous and thermal dissipations, num and χ num , which are later used for evaluating the constant of structure of the refraction index C 2 n following the classical model developed by Tatarski. Numerical examples show the behavior of the proposed numerical scheme when applied to turbulent flow practical cases, which include a convective boundary layer, the flow inside a transfer optics room, and a telescope enclosure.

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Second‐moment budgets in cloud topped boundary layers: A large‐eddy simulation study

Heinze

Mironov

Raasch

2015

J Adv Model Earth Syst

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A detailed analysis of second-order moment budgets for cloud topped boundary layers (CTBLs) is performed using high-resolution large-eddy simulation (LES). Two CTBLs are simulated-one with trade wind shallow cumuli, and the other with nocturnal marine stratocumuli. Approximations to the ensemble-mean budgets of the Reynolds-stress components, of the fluxes of two quasi-conservative scalars, and of the scalar variances and covariance are computed by averaging the LES data over horizontal planes and over several hundred time steps. Importantly, the subgrid scale contributions to the budget terms are accounted for. Analysis of the LES-based second-moment budgets reveals, among other things, a paramount importance of the pressure scrambling terms in the Reynolds-stress and scalar-flux budgets. The pressure-strain correlation tends to evenly redistribute kinetic energy between the components, leading to the growth of horizontal-velocity variances at the expense of the verticalvelocity variance which is produced by buoyancy over most of both CTBLs. The pressure gradient-scalar covariances are the major sink terms in the budgets of scalar fluxes. The third-order transport proves to be of secondary importance in the scalar-flux budgets. However, it plays a key role in maintaining budgets of TKE and of the scalar variances and covariance. Results from the second-moment budget analysis suggest that the accuracy of description of the CTBL structure within the second-order closure framework strongly depends on the fidelity of parameterizations of the pressure scrambling terms in the flux budgets and of the third-order transport terms in the variance budgets.

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Structure–Function Parameters in the Convective Boundary Layer from Large-Eddy Simulation

Cited by 38 publications

References 0 publications

The Effect of Surface Heterogeneity on the Structure Parameters of Temperature and Specific Humidity: A Large-Eddy Simulation Case Study for the LITFASS-2003 Experiment

The Effect of Surface Heterogeneity on the Structure Parameters of Temperature and Specific Humidity: A Large-Eddy Simulation Case Study for the LITFASS-2003 Experiment

Variational Multiscale based dissipation models for the estimation of atmospheric seeing

Second‐moment budgets in cloud topped boundary layers: A large‐eddy simulation study

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