atmospheric turbulence Articles

  • A Lagrangian stochastic model for estimating the high order statistics of a fluctuating plume in the neutral boundary layer

    We use a Lagrangian stochastic micromixing model to predict the concentration fluctuations of a continuous release in a neutral boundary layer. We present the computational algorithm that implements the interaction by exchange with the conditional mean model and we compare the numerical solutions with the experimental values in order to evaluate the reliability of the model. The influence of the ...


    By Inderscience Publishers

  • Boundary layer depth: sensitivity study

    The planetary boundary layer (PBL) height calculation is a two-step process. In the first one, the turbulence characteristics are evaluated either from direct measurements or through parameterisation schemes that use indirect measurements. In the second one, the PBL height is calculated using a model. For the convective PBL, simple models consider two parameters: the height and the temperature ...


    By Inderscience Publishers

  • Experimental study on flow and ventilation behaviours over idealised urban roughness

    Flows in the urban boundary layer (UBL) are strongly affected by the inhomogeneous roughness elements at the bottom surface. In particular, in the near-ground region (roughness sublayer), the effect of the surface roughness dominates that complicates the behaviours of mean flow and turbulence and subsequently the near-wall transport processes. To safeguard the health of urban inhabitants, it is ...


    By Inderscience Publishers

  • The 1998 IFDM evaluation with the model validation kit

    A modification of the Immission Frequency Distribution Model (IDFM) can reproduce the Kincaid and Indianapolis arc-wise maximum ground-level concentrations (GLCs) and crosswind integrated concentrations (CWICs) fairly well. But we doubt whether these modifications are really an improvement of the description of the natural ambient atmospheric dispersion process, rather than merely fitting a ...


    By Inderscience Publishers

  • Pollutant dispersion over two–dimensional idealised urban roughness: a large–eddy simulation approach

    A series of two–dimensional (2D) street canyon models with a wide range of building–height–to–street–width (aspect) ratios are employed in this study to elucidate the pollutant transport over idealised urban areas. The large–eddy simulation (LES) is used to resolve the turbulent flows and pollutant transport in the urban boundary layer (UBL) over the street canyons. The results show that the ...


    By Inderscience Publishers

  • Field experiments of flow and dispersion within a street canyon in outdoor urban scale model

    Field experiments of air flow and pollution dispersion within a street canyon in the Comprehensive Outdoor Scale Model (COSMO) facility were conducted to investigate the effect of the mean and turbulent flow above the canyon on pollutant dispersion inside the canyon. Tracer gas concentration was measured using fast–response photo ionisation detectors. Three–dimensional wind velocity components ...


    By Inderscience Publishers

  • Pre-processing of meteorological data: vertical profiles

    In the framework of COST-710, working group III aims to recommend formulations of atmospheric vertical profiles of wind, temperature and turbulence. This intermediate report gives a brief overview of existing methods to calculate vertical profiles. A short note on existing datasets for validation purposes is given.Keywords: atmospheric turbulence, turbulence time-, scale, vertical profiles, ...


    By Inderscience Publishers

  • Metek Introduces the New Multi-Path Ultrasonic Anemometers

    Our news report about recent instrumentations or measurements of our customers which might be of special interest for other web site visitors. The reports are added on the fly whenever we have received such information. The experienced support is highly welcome and appreciated. Metek is proud to present the new members of the uSonic-family: The ultrasonic anemometers uSonic-3 Class A ...

  • Canarina DISPER software · anaerobic digestion · commands 28

    The necessary data in the Meteorology command is:   Pasquill stability): Classification scheme that describes the degree of atmospheric turbulence. Categories range from extremely unstable (A=1) to extremely stable (F=6). Unstable conditions ...

  • Diurnal variation of the mixing-layer height and polonium concentration in the air

    The Mixing Height (MH) is one of the most important parameters that characterise the range of the atmospheric turbulence. This parameter shows characteristic diurnal variation but cannot be measured immediately. Therefore, it is evaluated indirectly by measuring other quantities. The measurement of radon concentration in the atmospheric air is one of the methods using natural occurring ...


    By Inderscience Publishers

  • Verification of the meteorological pre-processor MEPDIM

    The Norwegian Institute for Air Research (NILU) has carried out a year of direct measurements of standard deviations of wind fluctuations (σv and σw) on an island off the west coast of Norway. These measurements have been used for the evaluation of estimated values based on the meteorological pre-processor MEPDIM. The physical basis for this metprocessor is provided by parameterisation ...


    By Inderscience Publishers

  • A preliminary analysis of measurements from a near-field pollutants dispersion campaign in a stratified surface layer

    In order to study pollutants dispersion in a stably stratified surface layer at small scales, a pollutants dispersion field experiment programme is being conducted on the site SIRTA in the southern suburb of Paris. In a preliminary campaign held during the winter of 2012 with continuous gas releases, we had 12 ultrasonic anemometers measuring wind velocity and temperature at 10 Hz, and six ...


    By Inderscience Publishers

  • Some thoughts on in-situ flux measurement in the atmospheric surface layer

    Due to its complexity, the state of a turbulent atmosphere can only be described using statistical quantities such as means, variances, and covariances. Computation of these statistical quantities, particularly those of higher order, must be done with considerable care. This is particularly true if the statistics are used to depict heat and momentum fluxes. This note contains considerations that ...

  • Comparison of ISO 9613-2 vs Advanced Calculation Methods using Olive Tree Lab - Terrain

    Abstract The process of performing an Environmental Impact Assessment includes the study of noise propagation. Often, the path from a noise source to a noise sensitive location involves complicated mechanisms of sound transmission. These mechanisms may relate to diffraction & reflections from obstacles (natural or man made), ground properties, and meteorological conditions. The ...

  • A 2-D meteorological pre-processor for real-time 3-D ATD models

    Horizontal non-uniformity has important effects on the structure of the atmospheric boundary layer and, consequently, on pollutant transport and dispersion. These effects can be dominant in coastal sites or in the presence of complex terrain. Advanced 3-D atmospheric dispersion models can be used to calculate short-term pollutant concentrations in such complex situations. The use of new ...


    By Inderscience Publishers

  • Effects of meteorological parameters on RSPM concentration in urban Delhi

    The adverse effect of Respirable Suspended Particulate Matter (RSPM) has become a well-recognised problem in environmental science. Dispersion and dilution of air pollutants are strongly influenced by meteorological parameters, namely wind, turbulence, and atmospheric stability. The analysis of Delhi's air quality data shows that winter is the most critical season with respect to the ...


    By Inderscience Publishers

  • Photochemical smog modelling in Prague

    A model for simulation and evaluation of summer episodes of anthropogenic surface ozone (summer smog episodes) is presented in this paper. This model has been used for air-pollution studies in the region of Prague (central part of Bohemia, the Czech Republic). It is based on so-called "puff model" technology and the Lagrangian method of trajectory construction in the boundary layer of ...


    By Inderscience Publishers

  • Indicators of performance of dispersion models and their reference values

    A methodology of validation of dispersion models is analysed in this paper for situations when measurements, corresponding to a given set of governing meteorological parameters, are contaminated with stochastic noise resulting from the turbulent nature of atmospheric processes. Deterministic dispersion models in these situations predict certain non-stochastic values of concentrations and, ...


    By Inderscience Publishers

  • On the urban aspect of the Copenhagen dataset

    It was one of the findings from the model validation exercise during the third workshop 1994 in Mol that there was a common tendency for all models under consideration to underestimate the observed concentrations in the case of the Copenhagen dataset. It is argued here that this is due to the fact that this experiment was performed over a rough suburban surface. In such circumstances, a roughness ...


    By Inderscience Publishers

  • miniSODAR

    The miniSODAR is a high-frequency Doppler sodar system that was designed to measure the atmospheric wind profile from 15 meters to 150/200 meters (data is often available to 250 meters) in 5-meter increments. It operates by generating a short tone burst (30 ms to 100 ms) in the frequency range of 4 kHz to 6 kHz. It monitors the low-level acoustic signal echoed by the atmosphere. The echo is ...

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