atmospheric dispersion modeling Articles
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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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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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A review of evaluation procedures for atmospheric dispersion models
Evaluation of atmospheric dispersion models is vital to justify their use within the air quality component of environmental assessments. The Model Validation Kit, compiled and distributed by Helge Olesen of NERI, is often used for such evaluations. Whilst the Model Validation Kit has a wide range of functionality, its users often limit their evaluation to a few simplistic calculations. ...
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Atmospheric dispersion models for regulatory purposes in the Federal Republic of Germany. Part I: Regulatory modelling
The legal framework for the application of atmospheric dispersion models for air pollution control in Germany is outlined. Atmospheric dispersion models in regulatory procedures are currently essentially based on the Gaussian approach. However, more advanced modelling is already available.Keywords: air pollution control, atmospheric dispersion models, Gaussian model, Germany, regulatory ...
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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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Evaluation of statistical models in atmospheric dispersion modelling
When a gas is released into the atmosphere, there are inevitably random fluctuations in its concentration due to turbulence. Great recent improvements in instrumentation have shown how large these are. This has been acknowledged by CEC (the Commission of the European Communities), for example in that part of its Environment and Climate Programme (Framework IV) dealing with accidents. Likewise, ...
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Nuclear tools for characterising radiological dispersion in complex terrain: evaluation of regulatory and emergency response models
Routine operations of a nuclear research reactor and its facilities offer opportunities for collection of rare environmental tracer datasets which can be used for atmospheric dispersion model evaluation studies. The HIFAR reactor near Sydney, Australia, routinely emits the radioactive noble gas 41Ar, and other radionuclides such as 133Xe and 135Xe are also emitted from nearby radiopharmaceutical ...
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Investigation of the regulatory atmospheric dispersion model used in China, and its comparison with some other models
The regulatory atmospheric dispersion model used in China (CRADM) is briefly described, and the main differences between CRADM and the models used in western countries, such as HPDM and AMS, are analysed. The various aspects of CRADM, HPDM and AMS for same input are compared and discussed. Especially, it is indicated that the Briggs plume rise formula in neutral conditions overestimates the real ...
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Effective use of radiation monitoring data and dispersion calculations in an emergency
An essential prerequisite for the proper management of a radiation emergency is that measurement data and calculation prognoses are available and that they are produced in an efficient manner. This paper reviews some of the factors contributing to the practice of performing radiation measurements and atmospheric-dispersion-model calculations effectively and discusses the issues related to the ...
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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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Towards a new scheme for parametrisation of deep convection in NAME III
This paper describes an updated scheme for parametrisation of atmospheric convection to be used in the Met Office Atmospheric Dispersion Model (NAME III). In this scheme, the vertical transport of particles due to convection is represented in a 1-dimensional model based on a ‘mass-flux’ approach. Empirical formulas are used to obtain the mass fluxes and the convective precipitation is used for ...
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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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Contrasting methods for validating ADMS using the Indianapolis dataset
This paper shows results of validation of the Atmospheric Dispersion Modelling System (ADMS) against the Indianapolis dataset, comparing arcwise maxima and analysing the results using the BOOT statistical package. There is good agreement between the quality 3 daytime observed and predicted concentrations. At night-time, calculated concentrations depend critically on the value of the surface ...
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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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Comparative evaluation of two air quality models: within-regime evaluation statistic
At the Workshop on Operational Short-Range Atmospheric Dispersion Models for Environmental Impact Assessment in Europe, Lee and Irwin (1994) presented a methodology for conducting an objective comparative evaluation of two or more air quality models. The methodology involved the use of bootstrap resampling to allow computation of confidence bounds on model comparison measures, and an inverse ...
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A Nordic harmonisation effort concerning atmospheric dispersion modelling for real-time accident situations
Neighbouring countries have often chosen different atmospheric dispersion prognosis models for use in emergency situations. This may result in differences in the predictions, which in turn can lead to the authorities adopting different countermeasures. In a Nordic project within the Nordic Nuclear Safety Research Programme (NKS), a Nordic harmonisation and comparison effort was initiated in the ...
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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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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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Evaluation of new generation atmospheric dispersion models
The paper considers the regulatory view of evaluating dispersion models. There is no proscription for regulatory studies in the UK, so differences between dispersion calculations from different models and versions of models are then as important as their absolute veracity. An example shows variations in calculated concentration due to variations between two different versions of a model and two ...
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Validation of the improved AEROPOL model against the Copenhagen data set
The improved Gaussian dispersion model AEROPOL (University of Tartu, Estonia) is validated against the Copenhagen air pollution dispersion dataset belonging to the Model Validation Kit of the Initiative on "Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes". Model updates include the application of: surface heat flux instead of indirect indicators of surface layer ...
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