Similarity Theory, Intermittency and Turbulences in the Stable Boundary Layer

2005 ◽  
Vol 277-279 ◽  
pp. 618-624 ◽  
Author(s):  
Kyungm Ja Ha ◽  
Kyung Eak Kim ◽  
Yu Kyung Hyun ◽  
Eun Hee Jeon ◽  
Larry Mahrt
Keyword(s):  
Boundary Layer ◽  
Stable Boundary Layer ◽  
Similarity Theory ◽  
Similarity Relation ◽  
Stability Parameters ◽  
Stable Boundary ◽  
Flux Gradient ◽  
Stable Conditions ◽  
New Treatments ◽  
Theory Z

The evaluation of similarity theory, z-less formulation of turbulence, and validation for various stable conditions is addressed with the use of CASES99 data over grassland. The dependence of the flux-gradient relationships on height and stability parameters is evaluated. For very stable conditions, similarity relation based on Monin-Obukhov theory is locally invalid and new treatments are required. The flux intermittency is recommended as a good indicator of stability for very thin stable boundary layer.

scholarly journals Ventilation of a Mid-Size City under Stable Boundary Layer Conditions: A Simulation Using the LES Model PALM

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 401
Author(s):  
Jonathan Biehl ◽  
Bastian Paas ◽  
Otto Klemm
Keyword(s):  
Boundary Layer ◽  
Stable Boundary Layer ◽  
Passive Scalar ◽  
City Center ◽  
Street Canyons ◽  
Stable Boundary ◽  
Northwest Germany ◽  
Stable Conditions ◽  
Les Model ◽  
The City

City centers have to cope with an increasing amount of air pollution. The supply of fresh air is crucial yet difficult to ensure, especially under stable conditions of the atmospheric boundary layer. This case study used the PArallelized Large eddy simulation (LES) Model PALM to investigate the wind field over an urban lake that had once been built as a designated fresh air corridor for the city center of Münster, northwest, Germany. The model initialization was performed using the main wind direction and stable boundary layer conditions as input. The initial wind and temperature profiles included a weak nocturnal low-level jet. By emitting a passive scalar at one point on top of a bridge, the dispersion of fresh air could be traced over the lake’s surface, within street canyons leading to the city center and within the urban boundary layer above. The concept of city ventilation was confirmed in principle, but the air took a direct route from the shore of the lake to the city center above a former river bed and its adjoining streets rather than through the street canyons. According to the dispersion of the passive scalar, half of the city center was supplied with fresh air originating from the lake. PALM proved to be a useful tool to study fresh air corridors under stable boundary layer conditions.

scholarly journals The Critical Richardson Number and Limits of Applicability of Local Similarity Theory in the Stable Boundary Layer

2012 ◽  
Vol 147 (1) ◽  
pp. 51-82 ◽  
Author(s):  
Andrey A. Grachev ◽  
Edgar L Andreas ◽  
Christopher W. Fairall ◽  
Peter S. Guest ◽  
P. Ola G. Persson
Keyword(s):  
Boundary Layer ◽  
Stable Boundary Layer ◽  
Richardson Number ◽  
Similarity Theory ◽  
Local Similarity ◽  
Stable Boundary ◽  
Critical Richardson Number ◽  
Local Similarity Theory

scholarly journals Turbulent Velocity-Variance Profiles in the Stable Boundary Layer Generated by a Nocturnal Low-Level Jet

2006 ◽  
Vol 63 (11) ◽  
pp. 2700-2719 ◽  
Author(s):  
Robert M. Banta ◽  
Yelena L. Pichugina ◽  
W. Alan Brewer
Keyword(s):  
Boundary Layer ◽  
Stable Boundary Layer ◽  
Strong Wind ◽  
Surface Exchange ◽  
Stable Boundary ◽  
Low Level ◽  
Stable Conditions ◽  
Velocity Scale ◽  
Low Level Jet ◽  
Wind Profiles

Abstract Profiles of mean winds and turbulence were measured by the High Resolution Doppler lidar in the strong-wind stable boundary layer (SBL) with continuous turbulence. The turbulence quantity measured was the variance of the streamwise wind velocity component σ2u. This variance is a component of the turbulence kinetic energy (TKE), and it is shown to be numerically approximately equal to TKE for stable conditions—profiles of σ2u are therefore equivalent to profiles of TKE. Mean-wind profiles showed low-level jet (LLJ) structure for most of the profiles, which represented 10-min averages of mean and fluctuating quantities throughout each of the six nights studied. Heights were normalized by the height of the first LLJ maximum above the surface ZX, and the velocity scale used was the speed of the jet UX, which is shown to be superior to the friction velocity u* as a velocity scale. The major results were 1) the ratio of the maximum value of the streamwise standard deviation to the LLJ speed σu/UX was found to be 0.05, and 2) the three most common σ2u profile shapes were determined by stability (or Richardson number Ri). The least stable profile shapes had the maximum σ2u at the surface decreasing to a minimum at the height of the LLJ; profiles that were somewhat more stable had constant σ2u through a portion of the subjet layer; and the most stable of the profiles had a maximum of σ2u aloft, although it is important to note that the Ri for even the most stable of the three profile categories averaged less than 0.20. The datasets used in this study were two nights from the Cooperative Atmosphere–Surface Exchange Study 1999 campaign (CASES-99) and four nights from the Lamar Low-Level Jet Project, a wind-energy experiment in southeast Colorado, during September 2003.

scholarly journals The Innovative Strategies for Observations in the Arctic Atmospheric Boundary Layer Project (ISOBAR) —Unique fine-scale observations under stable and very stable conditions

2020 ◽  
pp. 1-64
Author(s):  
Stephan T. Kral ◽  
Joachim Reuder ◽  
Timo Vihma ◽  
Irene Suomi ◽  
Kristine Flacké Haualand ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Stable Boundary Layer ◽  
Unmanned Aircraft ◽  
Unmanned Aircraft Systems ◽  
The Arctic ◽  
Fine Scale ◽  
Stable Boundary ◽  
Innovative Strategies ◽  
Aircraft Systems ◽  
Stable Conditions

Capsule summaryCombining ground-based micrometeorological instrumentation with boundary layer remote sensing and unmanned aircraft systems for high-resolution observations on the stable boundary layer over sea ice and corresponding modelling experiments.

scholarly journals Diagnostic Equations for the Stable Boundary Layer Height: Evaluation and Dimensional Analysis

2007 ◽  
Vol 46 (2) ◽  
pp. 212-225 ◽  
Author(s):  
G. J. Steeneveld ◽  
B. J. H. van de Wiel ◽  
A. A. M. Holtslag
Keyword(s):  
Boundary Layer ◽  
Dimensional Analysis ◽  
Stable Boundary Layer ◽  
Surface Friction ◽  
Coriolis Parameter ◽  
Layer Height ◽  
Stable Boundary ◽  
Boundary Layer Height ◽  
Stable Conditions ◽  
Surface Buoyancy

Abstract The performance of diagnostic equations for the stable boundary layer height h is evaluated with four observational datasets that represent a broad range of latitudes, land use, and surface roughness. In addition, large-eddy simulation results are used. Special care is given to data-quality selection. The diagnostic equations evaluated are so-called multilimit equations as derived by Zilitinkevich and coworkers in a number of papers. It appears that these equations show a serious negative bias, especially for h < 100 m, and it was found that the parameters involved could not be determined uniquely with calibration. As an alternative, dimensional analysis is used here to derive a formulation for h that is more robust. The formulation depends on the surface friction velocity u*, surface buoyancy flux Bs, Coriolis parameter, and the free-flow stability N. The relevance of the Coriolis parameter for the boundary layer height estimation in practice is also discussed. If the Coriolis parameter is ignored, two major regimes are found: h ∼ u*/N for weakly stable conditions and h ∼ (|Bs|/N 3)1/2 for moderate to very stable conditions.

scholarly journals Areal-averaged trace gas emission rates from long-range open-path measurements in stable boundary layer conditions

2012 ◽  
Vol 5 (1) ◽  
pp. 1459-1496 ◽  
Author(s):  
K. Schäfer ◽  
R. H. Grant ◽  
S. Emeis ◽  
A. Raabe ◽  
C. von der Heide ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Land Surface ◽  
Stable Boundary Layer ◽  
Gradient Methods ◽  
Trace Gas ◽  
Emission Rates ◽  
Stable Boundary ◽  
Flux Gradient ◽  
Surface Emission ◽  
Flux Measurements

Abstract. Measurements of land-surface emission rates of greenhouse and other gases at large spatial scales (10 000 m2) are needed to assess the spatial distribution of emissions. This can be more readily done using spatial-integrating micro-meteorological methods than the widely-utilized small chamber measurements. Several micro-meteorological flux-gradient methods utilizing a non-intrusive path-averaging measurement method were evaluated for determining land-surface emission rates of trace gases under stable boundary layers. Successful application of a flux-gradient method requires confidence in the gradients of trace gas concentration and wind and in the applicability of boundary-layer turbulence theory. While there is relatively high confidence in flux measurements made under unstable atmospheres with mean winds greater than 1 m s−1, there is greater uncertainty in flux measurements made under free convective or stable conditions. The study involved quality-assured determinations of fluxes under low wind, stable or night-time atmospheric conditions when the continuous "steady-state" turbulence of the surface boundary layer breaks down and the layer has intermittent turbulence. Results indicate that the Monin-Obukhov similarity theory (MOST) flux-gradient methods that assume a log-linear profile of the wind speed and concentration gradient incorrectly determine vertical profiles and thus fluxes in the stable boundary layer.

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