dispersion modeling Articles
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Coupling of neural network and dispersion models: a novel methodology for air pollution models
Supervised neural net models and dispersion models are two important approaches for evaluating air pollution concentrations. The authors propose the development of an integrated model, in order to optimise the performances of each methodology. The concentrations evaluated by an air pollution model are coupled with a Neural Net (NN), so as to adjust the influence of important variables on ...
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Comparison of predictions of the Hybrid Plume Dispersion Model with observations at the Kincaid power plant
The Hybrid Plume Dispersion Model (HPDM) has been evaluated with observations from a field experiment at the Kincaid power plant. HPDM is a dispersion model for buoyant plumes that employs parameterisations of boundary-layer wind, temperature, and turbulence profiles and Lagrangian time-scales. The model accounts for the bimodal distribution of turbulent velocities in the convective boundary ...
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Study of turbulence and pollutant dispersion in a neutrally and unstably stratified atmosphere using a second-order closure boundary-layer model
A one-dimensional, mesoscale second-order closure boundary-layer model is developed to simulate wind flow in a horizontally homogeneous atmosphere. The velocity, potential temperature and turbulent kinetic energy are calculated prognostically, while other second-order moments are modelled diagnostically. The calculated turbulence is then treated as background turbulence to model the dispersion of ...
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Intercomparison of Lagrangian dispersion models and validation with Lillestrom data
Three different Lagrangian models (KLIMM-L, LASAT and STOER.LAG) are applied to the Lillestrom datasets. A pre-processing of the required vertical wind-profiles unifies the flow fields for the three models. In the framework of harmonisation the models show partial agreement with the datasets. The discrepancies are the same for all models. One reason for deviation of the datasets might be locally ...
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Validation of an operational advanced Gaussian model with the Copenhagen and Kincaid datasets
A practical model for evaluating ground-level concentrations from elevated sources that applies a new Gaussian formulation for transport and vertical diffusion is presented. In the Gaussian formula, the source height is replaced by a virtual source height, which is expressed by simple functions of the vertical profiles of wind and turbulent diffusivity. The performances of the model are evaluated ...
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Simulation of flow in an idealised city using various CFD codes
In the framework of the COST 732 action, several teams run models to verify the proposed Best Practice Guideline (Franke et al., 2007). The data set concerns the Mock Urban Setting Test (MUST) experiment, where wind field and dispersion measurements were conducted for an array of obstacles as a full-scale experiment, as well as in a wind tunnel. The pollutant transport research group at the ...
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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, ...
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On the wind flow patterns under neutral and unstable conditions in an urban area
Wind flow and pollutant dispersion within urban areas depend on the approaching flow profile and temperature stratification. Thus, the flow field developed under neutral and unstable stratification conditions, within a street–canyon, was studied experimentally and numerically for a two–dimensional urban background set–up. Wind–tunnel measurements were carried out with a triple hot sensor ...
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Effects of meteorological data thresholding on the quality of urban HPAC predictions of the Joint Urban 2003 field trials
Comparisons of field trial observations with predictions created by the US Defense Threat Reduction Agency's Hazard Prediction and Assessment Capability (HPAC) represent an ongoing effort. Intuitively, one might prefer to include meteorological inputs as close to the release location as possible. During Joint Urban 2003, SODARs measured vertical wind profiles?upwind, within the city centre near ...
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Operational short-range analytical air pollution modelling
Operational models that use solutions of the advection-diffusion equation based on more realistic assumptions than that of homogeneous wind and eddy diffusivity coefficients are presented. In particular, these solutions accept that wind and eddy diffusivity profiles are power functions of the height. Moreover, a practical short-range model evaluating ground-level concentrations from elevated ...
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Production of ozone in the Chamonix Valley (France)
In the framework of the Pollution of Alpine Valleys (POVA) programme, a numerical investigation aims to better understand how a reduction of traffic emissions can affect air quality in the Chamonix Valley (France). The MM5 model coupled with the Chemistry Transport Model (CTM) TAPOM using a 1-km cell grid for the period 5–12 July 2003 showed that the ozone formation in the Chamonix Valley was ...
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Potential Dispersion Modeling Uses of Archived NOAA Forecast Model Data
A newly-developed generation of air quality simulation models has the potential to use profiles of wind, temperature, and turbulence, as well as improved mixing height determination, measures of surface heat flux, and a host of other meteorological parameters. Several numerical weather prediction models that generate these comprehensive data sets are routinely being run by the National Oceanic ...
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Simple model of the Urban Atmospheric Boundary Layer (UABL)
The horizontally homogeneous atmospheric boundary layer over a rough surface with a large roughness length z0 has been investigated to model the simplest cases of the Urban Atmospheric Boundary Layer (UABL) over a flat plain. It has been demonstrated that the nondimensional profiles of the horizontal Reynolds stresses of eddy viscosity and of velocity defect components are universal and ...
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Evaluation of CALPUFF modelling system performance: an application over the Greater Athens Area, Greece
This study has been carried out in order to evaluate the performance of CALPUFF modelling system in an area of complex topography. For this reason a comparison was performed between numerical results produced by this modelling system and those derived by two Eulerian models (UAM-V and REMSAD), together with experimental measurements. The meteorological input parameters, produced by the ...
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Experimental study of turbulence and vertical temperature profile in the urban boundary layer
We observed the turbulence and vertical profile of temperature in and above the roughness sublayer (RS) using a tower, a tethered balloon and a Doppler sodar in Himeji City. A 3–D ultrasonic anemometer–thermometer was sited at a height of 54 m on the tower. The present results showed that in the RS, the ratio of friction velocity to wind speed, u* /u, observed under unstable conditions of −4.2 ...
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Computational modelling of airflow in urban street canyon and comparison with measurements
The main goal of this study was to predict the airflow in a street canyon surrounded by an urban area using CFD modelling. In the street geometry described in the main part, the actual airflow directly influences air infiltration into buildings. Different models of turbulence were tested as well as specific wind boundary conditions. A correct assignment of boundary conditions (i.e., mainly wind ...
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Zasavje canyon regional online air pollution modelling system in highly complex terrain - description and validation
Zasavje is an industrial region in Slovenia located along the Sava River's steep canyon where PM10 air pollution is a major problem. In the paper a national project with the title 'Prognostic and diagnostic integrated regional air pollution modelling system' is described where it is shown that such a project can significantly contribute to the proper understanding of air pollution in smaller ...
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Comparison between different dispersion models using wind-tunnel small-scale measurements
In this paper, the results from a plume diffusion experiment on a small-scale model of a two-stack waste incinerator, carried out in a developed boundary-layer wind-tunnel, will be presented. A brief description of the tunnel, the measurement system, and the artificially developed neutral boundary layer is given. The experiments investigate ground-level concentration measurements and vertical and ...
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Short–term fine resolution WRF forecast data validation in complex terrain in Slovenia
For the air pollution modelling studies over highly complex terrain, vertical wind profiles are essential. In the article we present evaluation about using the WRF model as the source of wind profile information. We tested WRF's one day short–term forecasts at 4 km and half hour resolution running every day to obtain 3D meteorological fields and compared these data with the different ...
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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 ...
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