IntroduçãoO controle da poluição atmosférica em escala local ou regional é realizado, usualmente, através de rede de monitoramento da qualidade do ar. Esta rede constitui um instrumento útil para a segurança da saúde humana e do ambiente, e permite analisar o benefício de ações de saneamento e predispor intervenções específicas no caso de acontecer superação dos níveis do limiar estabelecido pela legislação (MOREIRA; TIRABASSI, 2004a).Por motivos de caráter econômico e administrativo, o número de pontos de medida de uma rede é limitado e, acima de tudo, a disposição espacial delas pode não ter sido estudada cuidadosamente, podendo estar posicionada em um local pouco representativo. Por este motivo, os modelos matemáticos que simulam o transporte e a difusão dos poluentes na atmosfera constituem uma ferramenta importante para auxiliar as medidas de concentrações e saber a evolução das mesmas. Uma vez acertada a boa qualidade da resposta fornecida por um modelo, isto permite analisar a contribuição das diversas fontes para a poluição geral, e então endereçar corretamente eventuais ações de limitação das emissões. Somente com modelos matemáticos é possível fazer previsões ou simular campos de concentração em conexão com políticas de limitação da liberação de poluentes em concordância com planos de melhoria da qualidade de vida da população. A introdução da modelagem matemática produz um salto de qualidade na gestão da poluição atmosférica em respeito

This paper presents the MSDEF (Modelo Simulador da Dispersão de Efluentes de Foguetes, in Portuguese) model, which represents the solution for time-dependent advection-diffusion equation applying the Laplace transform considering the Atmospheric Boundary Layer as a multilayer system. This solution allows a time evolution description of the concentration field emitted from a source during a release lasting time t r , and it takes into account deposition velocity, first-order chemical reaction, gravitational settling, precipitation scavenging, and plume rise effect. This solution is suitable for describing critical events relative to accidental release of toxic, flammable, or explosive substances. A qualitative evaluation of the model to simulate rocket exhaust clouds is showed.

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In this work is presented a statistical description of wind profile in the first 100 m of height of the Planetary Boundary Layer, taking account the measurements in the tower Colonia Eulacio Uruguay. This tower has high vertical resolution of wind velocity measurements, form 10.1 m to 101.8 m. Thermometer are installed in 3.4 m and 100.8 m, also the tower is equipped with wind vane and pyranometer. We present the diurnal cycle of mean wind, intensity of turbulence in dependence of height, also standard deviation of direction is described as a measure of turbulence in wind. Stability state is computed with vertical gradient of temperature. Before sunrise (unstable condition) is seen a decrease in mean velocity of top levels (81.8 m and 101.8 m) and increase in lower levels (10.1 m and 25.7 m). Higher dispersion in dT/dz can be seen during night time (stable condition), superadiabatic values -0.02 ◦C/m can be seen during daytime with slow dispersion. Intensity of turbulence decrease with height, for all stability conditions, is seen a increase in intensity of turbulence for unstable condition.

This study simulates an unusual extreme rainfall event that occurred in Salvador City, Bahia, Brazil, on December 9, 2017, which was the subtropical storm Guará and had precipitation of approximately 24 mm within less than 1 h. Numerical simulations were conducted using the weather research and forecasting (WRF) model over three domains with horizontal resolutions of 9, 3, and 1 km. Different combinations of seven microphysics, three cumulus, and three planetary boundary layer schemes were evaluated based on their ability to simulate the hourly precipitation during this rainfall event. The results were compared with the data measured at the Brazilian National Institute of Meteorology (INMET) meteorological stations. The best configuration for the planetary boundary layer, cumulus, and microphysics schemes were Mellor-Yamada-Janjić, Grell-Devenyi, and Lin, respectively. The WRF model could depict the daily variations on the hourly parameters well, along with the spatial and temporal evolution of the extreme event.