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Hybrid Methods in Engineering

ISSN Print: 1099-2391
ISSN Online: 2641-7359

Archives: Volume 1, 1999 to Volume 4, 2002

Hybrid Methods in Engineering

DOI: 10.1615/HybMethEng.v4.i1-2.50
20 pages


Davidson M. Moreira
Universidade Federal dos Pampas, Unipampa Bagé; and Departamento de Engenharia Mecânica, Universidade Federal do Rio Grande do Sul, Brasil
J. C. Carvalho
Institute Nacional de Pesquisas Espaciais (INPE), Caixa Postal 515, 12201-970 São José dos Campos - SP, Brazil

Scientific Journal Referee
2001 - Present Journal: Ciencia e Natura
2005 - Present Journal: Atmospheric Environment
2003 - Present Journal: Revista Brasileira de Meteorologia
2004 - Present Journal: Water, Air and Soil Pollution
2006 - Present Journal: Revista Brasileira de Geofisica
2006 - Present Journal: Journal of Applied Meteorology (Boston)
2005 - Present Journal: Journal of Computational Physics
2004 - Present Journal: Environmental Modeling & Software
2007 - Present Journal: Atmospheric Research (0169-8095)
Gervasio Annes Degrazia
Departamento de Fisica, Universidade Federal de Santa Maria, Santa Maria; Consiglio Nazionale delle Ricerche, lstituto di Cosmo-Geofisica, Torino, Italy; and Universidade de Sao Paulo, Institute Astrondmico e Geofisico, Sao Paulo, Brazil
Marco T. Vilhena
Departamento de Engenharia Mecânica, Instituto de Matematica Aplicada, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
Marcelo Romero De Moraes
Centro de Informaçoes de Recursos Ambientais de Santa Catarina, Florianpólis, Brasil


Accounting for the current knowledge of the convective boundary layer (CBL) structure and characteristics, a simple semi-empirical formulation for the eddy diffusivity and dispersion parameter to be used in atmospheric dispersion models has been derived. That is, an expression for the dispersion parameter and eddy diffusivity depending on source distance for inhomogeneous turbulence in strongly unstable conditions is proposed. Yaglom's similarity theory is used to estimate these quantities. In addition, this vertical eddy diffusivity expression was introduced into an air pollution model, validated using data from the Prairie Grass experiments, and then compared with a Gaussian model. The results of this parameterization are shown to agree with the measurements of Prairie Grass and also with those of the Gaussian model. Furthermore, the present study suggests that the inclusion of the memory effect in Yaglom's similarity theory, which is important in near regions from a low continuous point source under strongly unstable conditions, improves the description of the turbulent transport process of atmospheric contaminants.