Model evaluation exercise for non-buoyant releases from continuous point sources
A model of the dispersion of pollutants released from a continuous point source into the atmospheric boundary layer is suggested. For this model and for that of Gryning et al. (1987), the predicted normalized crosswind integrated concentrations are compared with observational data. The data obtained...
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| Formato: | JOUR |
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| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_09574352_v14_n1-6_p143_Ulke |
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| Sumario: | A model of the dispersion of pollutants released from a continuous point source into the atmospheric boundary layer is suggested. For this model and for that of Gryning et al. (1987), the predicted normalized crosswind integrated concentrations are compared with observational data. The data obtained in diffusion experiments with a non-depositing tracer, in non-buoyant releases carried out at Copenhagen (Denmark), Cabauw (The Netherlands), Hanford (USA) and Lillestrom (Norway) have been used. The former two experiments were elevated releases during near neutral and unstable conditions; the latter two were near surface releases during near neutral and stable conditions. The comparison is done with each dataset and with the full database. Statistical measures and techniques of model evaluation are obtained and applied. The behaviour of residuals with some meteorological parameters is studied. The overall agreement between estimated and measured concentrations is satisfactory. The models have quite similar performances. A dispersion model, based on the bi-dimensional semi-empirical equation, is outlined for modeling pollutants released into the atmospheric boundary layer. The model is based on the advection-diffusion equation and makes use of a parameterization that gives continuous values over the full range of height and stability conditions. Results are presented from an evaluation of the model using data sets generated in Copenhagen, Denmark; Cabauw, Netherlands; Hanford, WA, USA; and Lillestrom, Norway. All of the studies involved sulfur hexafluoride in nonbuoyant releases from several source heights and under a range of atmospheric stability conditions. Results show that the proposed model and that developed by Gryning et al. performed similarly. However, the proposed model makes use of a continuous description of dispersion in the various regimes of the boundary layer, which overcomes the problems posed by the discrete modeling approach. (from Fifth Workshop on Harmonization Within Atmospheric Modelling for Regulatory Purposes, Rhodes, Greece (May 18-21, 98)). |
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