Convective Velocity and Temperature Scales for the Unstable Planetary Boundary Layer and for Rayleigh Convection

Deardorff, J. W.

doi:10.1175/1520-0469(1970)027<1211:cvatsf>2.0.co;2

Cited by 569 publications

(347 citation statements)

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“…Here, U r is the actual measured or modelled mean magnitude of the vector wind at reference height r, β g = 1.25 (Fairall et al, 1996), and w * is Deardorff's (1970) convective velocity scale (Godfrey and Beljaars, 1991):…”

Section: Bulk Flux Algorithmmentioning

confidence: 99%

Parametrizing turbulent exchange over summer sea ice and the marginal ice zone

Andreas

Horst

Grachev

et al. 2010

Q.J.R. Meteorol. Soc.

157

188

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The surface of the Arctic Ocean in summer is a mix of sea ice and water in both leads and melt ponds. Here we use data collected at multiple sites during the year-long experiment to study the Surface Heat Budget of the Arctic Ocean (SHEBA) to develop a bulk turbulent flux algorithm for predicting the surface fluxes of momentum and sensible and latent heat over the Arctic Ocean during summer from readily measured or modelled quantities. The distinctive aerodynamic feature of summer sea ice is that the leads and melt ponds create vertical ice faces that the wind can push against; momentum transfer to the surface is thus enhanced through form drag. In effect, summer sea ice behaves aerodynamically like the marginal ice zone, which is another surface that consists of sea ice and water. In our bulk flux algorithm, we therefore combine our SHEBA measurements of the neutral-stability drag coefficient at a reference height of 10 m, C DN10 , with similar measurements from marginal ice zones that have been reported in the literature to create a unified parametrization for C DN10 for summer sea ice and for any marginal ice zone. This parametrization predicts C DN10 from a second-order polynomial in ice concentration. Our bulk flux algorithm also includes expressions for the roughness lengths for temperature and humidity, introduces new profile stratification corrections for stable stratification, and effectively eliminates the singularities that often occur in iterative flux algorithms for very light winds. In summary, this new algorithm seems capable of estimating the friction velocity u

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Section: Bulk Flux Algorithmmentioning

confidence: 99%

Parametrizing turbulent exchange over summer sea ice and the marginal ice zone

Andreas

Horst

Grachev

et al. 2010

Q.J.R. Meteorol. Soc.

157

188

View full text Add to dashboard Cite

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“…In the dry daytime convective boundary layer, the vertical scale of the largest turbulent eddies is on the order of the mixed-layer height z i , and their velocity scale is on the order of the Deardorff convective velocity scale, (Deardorff 1970;Young 1988). Here g is gravitational acceleration, θ 0 is a reference potential temperature, and H is the magnitude of the surface sensible heat flux.…”

Section: C) Analysis Planmentioning

confidence: 99%

Exploration of the impact of nearby sources on urban atmospheric inversions using large eddy simulation

Gaudet

Lauvaux

Deng

et al. 2017

Elementa: Science of the Anthropocene

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The Indianapolis Flux Experiment (INFLUX) aims to quantify and improve the effectiveness of inferring greenhouse gas (GHG) source strengths from downstream concentration measurements in urban environments. Mesoscale models such as the Weather Research and Forecasting (WRF) model can provide realistic depictions of planetary boundary layer (PBL) structure and flow fields at horizontal grid lengths (Δx) down to a few km. Nevertheless, a number of potential sources of error exist in the use of mesoscale models for urban inversions, including accurate representation of the dispersion of GHGs by turbulence close to a point source.Here we evaluate the predictive skill of a 1-km chemistry-adapted WRF (WRF-Chem) simulation of daytime CO 2 transport from an Indianapolis power plant for a single INFLUX case (28 September 2013). We compare the simulated plume release on domains at different resolutions, as well as on a domain run in large eddy simulation (LES) mode, enabling us to study the impact of both spatial resolution and parameterization of PBL turbulence on the transport of CO 2 . Sensitivity tests demonstrate that much of the difference between 1-km mesoscale and 111-m LES plumes, including substantially lower maximum concentrations in the mesoscale simulation, is due to the different horizontal resolutions. However, resolution is insufficient to account for the slower rate of ascent of the LES plume with downwind distance, which results in much higher surface concentrations for the LES plume in the near-field but a near absence of tracer aloft. Physics sensitivity experiments and theoretical analytical models demonstrate that this effect is an inherent problem with the parameterization of turbulent transport in the mesoscale PBL scheme. A simple transformation is proposed that may be applied to mesoscale model concentration footprints to correct for their near-field biases. Implications for longer-term source inversion are discussed.

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“…LES data have been found to be very useful in numerous studies of the ABL (e.g. Deardorff 1970;Wyngaard and Brost 1984;Andren et al 1994;Kosovic and Curry 2000;Ding et al 2001;Zilitinkevich and Esau 2003;Mauritsen et al 2007).…”

Section: Les Datamentioning

confidence: 99%

Improvement of Vertical Diffusion Analytic Schemes Under Stable Atmospheric Conditions

Jeričević

Večenaj

2009

Boundary-Layer Meteorol

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Based on gradient transport theory or K-theory, turbulent transport in the atmosphere has long been parameterized using the eddy diffusivity. Due to its simplicity, this approach has often been applied in many numerical models but rarely tested with observations. Here, the widely used O'Brien cubic polynomial approach has been validated together with an exponential approach against eddy diffusivity profiles determined from measurements and from large-eddy simulation data in stable conditions. Verification is completed by analyzing the variability effects on pollutant concentrations of two different vertical diffusion (K (z)) schemes incorporated in an atmospheric chemical model. It is shown that the analytical, exponential solution agrees better with observations than the O'Brien profile and should be used henceforth in practical applications.

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Convective Velocity and Temperature Scales for the Unstable Planetary Boundary Layer and for Rayleigh Convection

Cited by 569 publications

References 0 publications

Parametrizing turbulent exchange over summer sea ice and the marginal ice zone

Parametrizing turbulent exchange over summer sea ice and the marginal ice zone

Exploration of the impact of nearby sources on urban atmospheric inversions using large eddy simulation

Improvement of Vertical Diffusion Analytic Schemes Under Stable Atmospheric Conditions

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