dispersion modeling Articles
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The Austrian guideline for short scale dispersion modelling
Dispersion modelling during licensing procedures is, due to the limited time frame, a rather challenging task. Complex building structures or source configurations, which call for sophisticated dispersion models require usually long computation times. A new modelling tool for such applications has been developed in Austria, which is based on simulations for 34 pre–defined source ...
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Validation of DIPCOT-II model based on the Kincaid experiment
This study presents the performance of the Lagrangian particle dispersion model DIPCOT-II (DIsPersion over COmplex Terrain) at the Kincaid field experiment. The validation of the model is performed on the basis of the maximum arcwise and near centreline concentrations using the bootstrap re-sampling procedure and the variation of the model residuals.Keywords: Kincaid experiment, Lagrangian ...
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`Top 10 Things You Should Be Asking Your Dispersion Modeler Now,` presented at the 2008 FET Conference
Agenda Introduction to Modeling (short course) Top 10 List – Questions you should beasking your dispersion modeler Introduction to Modeling Definition Why Model? Types of Models AERMOD background Definition Dispersion modeling is a technique ofcalculating concentrations of pollutantsresulting from emissions to the atmosphere Easy if a single isolated stack ...
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The harmonisation of gas dispersion modelling for industrial applications: a few thoughts for the future
The Gas Dispersion Modelling Harmonisation Initiative has been successful in highlighting significant differences between models for quantifying the dispersion of gaseous emissions. Possible areas for developing the initiative further are detailed in this paper. The key issues raised are: a) The need for a definitive set of full-scale experiments to quantify dispersion from stacks with heights in ...
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Validation study of the dispersion Lagrangian particle model DIPCOT over complex topographies using different concentration calculation methods
In this paper, the Lagrangian particle dispersion model DIPCOT is evaluated by simulating two dispersion experiments over highly complex topographies (the TRANSALP90 and the ETEX experiments). The resulting predicted concentrations were compared with the experimental ones using some well-known performance indices and various types of plots. Furthermore the model results are compared to the ...
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SMEDIS: scientific model evaluation of dense gas dispersion models
SMEDIS is a project currently in progress to develop a protocol for the scientific evaluation of dense gas dispersion (DGD) models, with particular emphasis on the complex effects of obstacles, terrain and aerosols often found in real situations, and then to apply this protocol to DGD models currently in use in Europe. This paper describes the general features of a model evaluation project and ...
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Validation of models AEROFOUR and AEROPOL using the model validation kit established at Mol
The AEROPOL and AEROFOUR dispersion models developed at Tartu Observatory (Estonia) are validated using the Lillestrom dataset and following the model comparison rules established at the workshop in Mol. Running the AEROFOUR model, the vertical wind and temperature co-variations not included into the official dataset were used. The computed and measured arc-wise maximum and crosswind integrated ...
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Validation of the Gaussian puff models TSTEP and REM-3 using the Kincaid dataset
Two Gaussian short-range atmospheric dispersion models, TSTEP and REM-3, have been validated with the Kincaid dataset of the Model Validation Kit. TSTEP and REM-3 show high scatter compared to the observations. Both models have the tendency to underestimate lower concentratrations and to overestimate higher concentrations, but, within a factor of five, many predictions are in agreement with the ...
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Validation of the Demokritos dispersion modelling system based on the Indianapolis experiment
To assess the ability of a model to simulate atmospheric dispersion, its performance must be tested using data from real field experiments. This paper presents the results of a validation study of the atmospheric dispersion model Dispersion over Complex Terrain (DIPCOT) against data from the Indianapolis field experiment. Three different modules of the dispersion code are examined a puff model, a ...
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CEC model evaluation group: an account of the activities of the Heavy Gas Dispersion Expert Group
The heavy gas dispersion expert group is one of the three groups so far set up by the CEC Model Evaluation Group. This paper describes the activities of the group. The main results of these activities are: (i) a tested heavy gas dispersion model evaluation protocol, (ii) a list and classification of available models and (iii) a list and classification of relevant datasets.Keywords: heavy gas ...
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The Model Validation Kit - status and outlook
Over the past few years, the so-called Model Validation Kit has been the basis for much work on evaluation of atmospheric point source dispersion models. The kit has recently been enhanced with a supplement which represents urban conditions (experimental data from Indianapolis, USA). A change of methodology is under consideration, based on the concept of near centreline concentrations. The paper ...
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Recent studies to validate and compare atmospheric dispersion models for regulatory purposes in the UK
Some results are presented for recent studies to develop new approaches for (i) validating atmospheric dispersion models using crosswind concentration transects, and (ii) summarising and comparing the predictions of models across a range of efflux and meteorological conditions.Keywords: crosswind concentration, dispersion climate, dispersion modelling, ...
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Consolidating tools for model evaluation
An overview is provided of some central tools and data sets that are currently available for evaluation of atmospheric dispersion models. The paper serves as a guide to the Model Validation Kit, which was introduced already in 1993, but has undergone a recent revision. The Model Validation Kit is a package of field data sets and software for model evaluation plus various supplementary materials. ...
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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, ...
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Improving The Accuracy Of Dispersion Models
Ever since dispersion models were first developed over 30 years ago, their accuracy has been subject to scrutiny. If automobile speedometers are accurate within five percent and orifice meters are accurate within about one percent, why can’t dispersion models be just as accurate? The early documents on dispersion modeling referred to accuracy as a “factor of 3.”(1) By the 1970’s, dispersion ...
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Using plume rise schemes to model highly buoyant plumes from large fires
The atmospheric dispersion model Numerical Atmospheric-dispersion Modelling Environment (NAME) is used to simulate the smoke plume from the explosion at the Buncefield oil depot. Simple modelling, in which the plume rise is included through an effective elevated source term, captures the transport and spread of the plume well. More complex modelling, using the NAME plume rise scheme, ...
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Mesoscale transport of air pollutants over Athens: implications for air quality
Air pollutants released from sources located near and around extensive conurbations such as the Athens Metropolitan Area, can be transported over them under various atmospheric conditions. Some of the industrial sources located to the north-east of Athens are directly responsible for the transport and dispersion of a large number of pollutants. In this paper the result of a number of simulations ...
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A new puff modelling technique for short range dispersion applications
A puff model is proposed for short range dispersion applications. The model aims to reproduce the results of a stochastic Lagrangian particle model while avoiding to a large extent the noise which is often present in Lagrangian particle models. Part of the dispersion is modelled through the growth of the puffs while part is treated by a random motion of the puff centres. Comparisons with a ...
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Gas dispersion modelling harmonisation: an industrial viewpoint
The harmonisation of gas dispersion modelling across Europe requires not only harmonisation of the physics incorporated into different mathematical models but also harmonisation of the way that practitioners actually use these models. This paper highlights the need to define minimum acceptable standards for gas dispersion modelling, especially in the specification of source conditions and ...
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Comparison of two point–to–point protocols for transport and dispersion model evaluations
Historically, assessments of transport and dispersion models have involved comparisons to field trial data using quantities derived from observations - e.g., maximum concentrations or plume widths. Recently, several methodologies that compare observations and predictions paired in space and time have been developed. Two protocols designed to deal with low observed or predicted values have ...
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