Flux‐gradient relationships in the constant flux layer

Dyer, A. J.; Hicks, B. B.

doi:10.1002/qj.49709641012

Cited by 891 publications

(460 citation statements)

References 12 publications

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“…According to Large Eddy Simulations [24] and many field experiments [3,[25][26][27], φ m (ζ) = (1 − 16ζ) −1/4 when ζ < 0 and φ m (ζ) = (1 + 4.7ζ) when ζ > 0. A derivation of these φ m (ζ) functions and their links to the energy spectrum is presented elsewhere [28] and is not repeated here.…”

Section: A Background and Definitionsmentioning

confidence: 99%

Mean scalar concentration profile in a sheared and thermally stratified atmospheric surface layer

Katul

Chameki

et al. 2013

Phys. Rev. E

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Using only dimensional considerations, Monin and Obukhov proposed a 'universal' stability correction function φc(ζ) that accounts for distortions caused by thermal stratification to the mean scalar concentration profile in the atmospheric surface layer when the flow is stationary, planar homogeneous, fully turbulent, and lacking any subsidence. For nearly six decades, their analysis provided the basic framework for almost all operational models and data interpretation in the lower atmosphere. However, the canonical shape of φc(ζ) and the departure from the Reynold's analogy continue to defy theoretical explanation. Here, the basic processes governing the scalar-velocity cospectrum, including buoyancy and the scaling laws describing the velocity and temperature spectra, are considered via a simplified co-spectral budget. The solution to this co-spectral budget is then used to derive φc(ζ), thereby establishing a link between the energetics of turbulent velocity and scalar concentration fluctuations and the bulk flow describing the mean scalar concentration profile. The resulting theory explains all the canonical features of φc(ζ), including the onset of power-laws for various stability regimes and their concomitant exponents, as well as the causes of departure from Reynold's analogy.

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Section: A Background and Definitionsmentioning

confidence: 99%

Mean scalar concentration profile in a sheared and thermally stratified atmospheric surface layer

Katul

Chameki

et al. 2013

Phys. Rev. E

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“…ϕ m , ϕ h : Dyer and Hicks (1970) in unstable conditions (ς < 0), and Kondo et al (1978) in stable conditions (ς > 0).…”

Section: The Campaignmentioning

confidence: 99%

Trade-offs and responsiveness of the single-layer urban canopy parametrization in WRF: An offline evaluation using the MOSCEM optimization algorithm and field observations

Loridan

Grimmond

Grossman‐Clarke

et al. 2010

Q.J.R. Meteorol. Soc.

103

143

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For an increasing number of applications, mesoscale modelling systems now aim to better represent urban areas. The complexity of processes resolved by urban parametrization schemes varies with the application. The concept of fitness-forpurpose is therefore critical for both the choice of parametrizations and the way in which the scheme should be evaluated. A systematic and objective model response analysis procedure (Multiobjective Shuffled Complex Evolution Metropolis (MOSCEM) algorithm) is used to assess the fitness of the single-layer urban canopy parametrization implemented in the Weather Research and Forecasting (WRF) model. The scheme is evaluated regarding its ability to simulate observed surface energy fluxes and the sensitivity to input parameters. Recent amendments are described, focussing on features which improve its applicability to numerical weather prediction, such as a reduced and physically more meaningful list of input parameters. The study shows a high sensitivity of the scheme to parameters characterizing roof properties in contrast to a low response to road-related ones. Problems in partitioning of energy between turbulent sensible and latent heat fluxes are also emphasized. Some initial guidelines to prioritize efforts to obtain urban land-cover class characteristics in WRF are provided.

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“…Computation of surface fluxes of heat, moisture and momentum are based on Monin-Obukhov similarity theory using the stability functions from Paulson (1970), Dyer and Hicks (1970) and Webb (1970). Vertical transport and mixing in the boundary layer are accounted for by using the YSU-PBL scheme (Hong and Lim, 2006).…”

Section: Experimental Set-upmentioning

confidence: 99%

Impact of different initial conditions on the growth of polar lows: idealised baroclinic channel simulations

Adakudlu¹

2011

Quart J Royal Meteoro Soc

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The development of a polar low is simulated in an ideal baroclinic channel with the objective of studying the relative influence of different initial conditions on certain characteristics of the polar low. The basic state in the channel has a baroclinic jet at the tropopause level superposed by potential vorticity anomalies. The upperlevel perturbation leads to the genesis of a polar low through baroclinic instability. During its growth, the polar low is driven by a combination of baroclinic and convective processes as the vertical motion associated with the polar low is found to be forced simultaneously by the adiabatic and diabatic omega-forcing terms in the quasi-geostrophic omega equation. The degree of baroclinicity, surface heating and the scale of the upper-level anomaly were each reduced, and static stability increased separately in a series of sensitivity experiments. The results show that the pattern of the vertical motion, the growth rate and phase speed of the polar low are highly sensitive to the modifications in the background conditions. In particular, the surface temperature and baroclinicity appear to be crucial in determining the strength of the vertical motion associated with the polar low. The scale and structure of the polar low are more vulnerable to the scale of the upper-level anomaly and initial baroclinicity than to the rest of the parameters tested. In all the sensitivity experiments, the formation of the polar low gets delayed and its intensity, in terms of the surface pressure, reduced due to the modified initial conditions. The

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Flux‐gradient relationships in the constant flux layer

Cited by 891 publications

References 12 publications

Mean scalar concentration profile in a sheared and thermally stratified atmospheric surface layer

Mean scalar concentration profile in a sheared and thermally stratified atmospheric surface layer

Trade-offs and responsiveness of the single-layer urban canopy parametrization in WRF: An offline evaluation using the MOSCEM optimization algorithm and field observations

Impact of different initial conditions on the growth of polar lows: idealised baroclinic channel simulations

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