atmospheric modeling Articles
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Saharan desert dust radiative effects: a study based on atmospheric modelling
This work investigates the Saharan desert storms direct effect, through the assessment of regional-scale Desert Dust (DD) aerosol Radiative Forcing (RF). Simulated parameters, obtained from atmospheric modelling, are used. The effect over different surfaces on the dust RF is analysed and the stratospheric ozone is considered. In the presence of DD aerosols, a shortwave cooling and a longwave ...
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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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The domino effect in climate change
This paper provides a concise summary of the natural and the anthropogenic greenhouse effect and the major causes for climate change. This summary may be particularly accessible for readers who are not familiar with natural sciences. Building on these explanations, we develop a simplifying atmospheric model that demonstrates a widely unknown aspect of global warming: the greenhouse effect ...
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On the numerical asymmetry in calculating Coriolis terms through the splitting method in a mesoscale model
The asymmetry in calculating the Coriolis terms by Marchuk's splitting method is discussed. It was found that although some asymmetry is required for linear stability, this asymmetry should be kept to a minimum. Otherwise, for instance, if the diffusion terms are calculated in between the Coriolis terms in the u and v equations of motion, one gets cross-isobaric low-level winds, which are ...
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Uncertainty analysis of modelling studies included in air quality assessments
This paper deals with the development of a quality analysis/quality control (QA/QC) methodology for modelling studies associated with air quality assessments. Among other benefits, this will allow data quality objectives for model input data to be derived and the importance of policy oriented model applications to be assessed. The procedure for evaluating model uncertainty has profited from a ...
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The "Tracer Potential" method of evaluating atmospheric models: main algorithms
In this paper, we describe the basic concepts and main algorithms of a method which uses tracer measurements to compare and evaluate wind fields as predicted by different atmospheric models or obtained from measurements. In particular, we focus on details of the trajectory calculation and the estimation of the relative and absolute successes of the wind fields. A cost function "Tracer ...
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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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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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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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Mesoscale modelling of atmospheric processes over the western Mediterranean area during summer
The EC's MECAPIP project served to identify some aspects of the summer atmospheric circulations and associated air pollution dynamics over the Iberian peninsula. The Regional Atmospheric Modelling System (RAMS) was applied to reproduce the mesoscale meteorological processes around the Iberian peninsula and its link with the synoptic circulation. In this paper, modelled results initialised with ...
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On efficient numerical solution of one-dimensional convection?diffusion equations in modelling atmospheric processes
A new approach is proposed to the numerical solution of one-dimensional convection?diffusion equations that arise in modelling atmospheric processes and air pollution modelling. The technique is based on upstream-type difference approximations for first-order derivatives and non-standard difference approximations for second-order derivatives of convection?diffusion equations. This approach leads ...
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Projected precipitation and air temperature over Europe using a performance-based selection method of CMIP5 GCMs
An assessment of the plausible climate change in precipitation and surface air temperature (SAT) over the European region by the end of the 21st century is provided. The assessment is based on the results of output of the ocean–atmosphere models participating in the Coupled Model Intercomparison Project, phase 5 (CMIP5). Six climate models that best reproduce the historical behaviour of SAT ...
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The main principles of atmospheric diffusion modelling for regulatory purposes in Russia
This paper discusses the main principles of atmospheric diffusion modelling for regulatory purposes in Russia. They include the choice of air quality criteria, the development of universal models to calculate on a single base the dispersion of atmospheric pollutants from different types of source under unfavourable meteorological and topographical conditions, as well as experimental verification ...
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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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Implementation of a two-way coupled atmospheric-hydrological system for environmental modeling at regional scale
This work describes the two-way coupling performed between the regional atmospheric model Brazilian Regional Atmospheric Modeling System (BRAMS) and the hydrological model MGB-IPH. As a first step of the atmosphere-hydrology coupling, only the water balance variables were coupled. Differences in temporal and spatial scales between MGH-IPH and BRAMS were analyzed. By default, MGB-IPH has a daily ...
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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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Aermod View - Working With Different Model Versions in Aermet View
With each successive update to the AERMOD modeling system published by the U.S. EPA to the Support Center for Regulatory Atmospheric Modeling (SCRAM) website, Lakes Software updates our AERMOD View and AERMET View applications to support the new models. In previous Modeling Tips, we’ve discussed how to choose earlier versions of the AERMOD executable in AERMOD View, but it is also possible ...
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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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An analysis of the meteorological and air quality conditions during an extreme ozone episode over the north-eastern USA
In this study, an extreme ozone episode that occurred during the period 12-15 July 1995 over the north-eastern United States is investigated through model simulations. This paper is focused on the meteorological conditions prevailing during this ozone episode. The analysis is based on nested grid simulations performed with the meteorological model CSU-RAMS (Colorado State University - Regional ...
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