Edmilson D. Freitas

Air quality forecasting system for Southeastern Brazil

Southeastern Brazil, the most populous and developed region of the country, faces various environmental problems associated with the growth of its population in urban areas. It is the most industrialized area in the country, comprising the metropolitan areas of Sao Paulo, Rio de Janeiro, Belo Horizonte, and other major cities. Air quality is a major concern, because the reported concentrations of certain regulated pollutants, typically ozone and fine particulate, have exceeded national standards. Due to the difficulty in taking measurements over many different areas, air quality modeling is a useful tool to estimate air pollutant concentrations. For southeastern Brazil, air quality modeling has been performed mostly with the Brazilian Regional Atmospheric Modeling System with Simplified Photochemical Module and the Weather Research and Forecast with Chemistry models. One of the main objectives was to study the evolution of air quality associated with improved vehicle emission factors in urban areas, the impact of climate change on air quality, and the relationship between pollutant concentrations and health. Knowledge of mobile source emission factors has been continuously expanded by in-tunnel measurements and dynamometer protocols, which provide accurate data as inputs to photochemical air quality models. The spatial distribution of the mobile source emissions was constructed based on open access data related to the streets and traffic distribution. The mobile emission module was combined to the chemistry modeling and this implementation can be an example to be applied to other places that do not have a spatial distribution of this kind of source. Forecasts of pollutant concentrations can inform public policies, including those addressing the effects of pollutants on health of the general population, and studies of the impacts of using different fuels and implementation of emissions regulations programs.

Influence of local circulations on wind, moisture, and precipitation close to Manaus City, Amazon Region, Brazil

This paper presents long-term-derived local wind patterns as well as their role on moisture transport and on spatial/temporal distribution of precipitation close to Manaus City region. In this analysis we used surface weather station data and rainfall estimates from TRMM (Tropical Rainfall Measuring Mission) and CMORPH (Climate Prediction Center morphing method). The weather stations promoted information of wind direction and dew point temperature, used here as atmospheric moisture indicator. The 3-hourly average of accumulated precipitation, calculated using satellite estimates (TRMM and CMORPH), allowed to assess the spatial distribution of the rainfall diurnal cycle and how it is modulated by the local circulations. The station data results show that in the daytime, between 9:00 and 18:00 local time, winds away from the rivers are frequent, indicating action of the river breeze. This wind condition transports moist air from the rivers to the Manaus City. Winds toward rivers are commonly observed at night and in the morning, mostly at Ponta Pelada airport station, and are evidence of the land breeze occurrence. These local winds transport drier air from Manaus City to the river regions, as verified at Ponta Pelada station. The evidence of the local circulations and their impact on the moisture transport are more obvious in the dry season. The rainfall diurnal cycle has a spatial tendency varying according to the hour of the day. In the afternoon and in the evening, maximum precipitation values are observed over land, whereas reduced rainfall values are verified over rivers. At dawn and in the morning, the maximum values of accumulated precipitation are found over the rivers, mainly over and around the Amazon River. This rainfall spatial distribution is very likely modulated by local circulations and is much more evident in the rainiest quarter (March–May).

The relationship between South Atlantic SST and SACZ intensity and positioning

This study explores the ocean–atmosphere interaction in the formation and dynamics of the South Atlantic Convergence Zone (SACZ), through the analysis of the heat sources estimated through the outgoing longwave radiation. The results obtained with this study show that the coupled variability between SACZ and the South Atlantic Ocean indicates that in northern positioned SACZ cases (over Southeastern Brazil), westerly anomalies are verified in the low level continental tropical circulation, consistent with the active phase of the South America Monsoon System (SAMS). In these cases, cold anomalies in the subtropical Atlantic Ocean cause an increase in the continent–ocean temperature gradient, favoring an easterly flow in this region, and blocking the SACZ at a northerly position. Easterly anomalies in the tropical continent were verified in the low level circulation in southern positioned cases (over Southern Brazil), consistent with the SAMS break phase. The SST anomaly patterns indicate cold anomalies in the tropics and warm anomalies in the subtropics, which do not favor the development of an easterly flow at low levels over the western tropical Atlantic. In these cases, two situations may occur: the strengthening of the Low Level Jet (LLJ), which prevails in the eastern subtropical South America and convergence with the South Atlantic Subtropical High at its southern position; or the atmospheric unstable conditions caused by ocean warm SST anomalies (in this case the LLJ may be weaker than its climatological intensity).

South America Land Use and Land Cover Assessment and Preliminary Analysis of Their Impacts on Regional Atmospheric Modeling Studies

Data provided by two important sources of information on land use and land cover (LULC), MODIS-2009 and GLOBCOVER-2009, were analyzed for South America in order to assess differences related to their application in numerical modeling studies. Even though on a South American basis, the two databases showed a Pearson correlation coefficient above 85%, on a regional analysis, the correlation stayed within the range of 0%-100%, depending on the territorial unit analyzed. Significant differences were observed in most of the land cover classes, with only forested areas presenting a good level of agreement. In terms of territorial units, only areas in the Amazon region, where forest cover is predominant, showed significant correlation levels. Crops and urban classes presented the greatest differences between the two analyzed files. Results of meteorological simulations indicated that such observed discrepancies are able to cause strong impacts on modeling scenarios and important bias on simulated variables, being a crucial feature for weather and climate forecast and diagnostic.

AVALIAÇÃO DA INFLUÊNCIA DE CONDIÇÕES METEOROLÓGICAS NA OCORRÊNCIA E MANUTENÇÃO DE UM EPISÓDIO PROLONGADO COM ALTAS CONCENTRAÇÕES DE OZÔNIO SOBRE A REGIÃO METROPOLITANA DE SÃO PAULO

In the Metropolitan Area of Sao Paulo, air quality monitoring network often register ozone concentration values higher than those established by Brazilian legislation. In some occasions, weather conditions favorable to ozone formation allow the occurrence of high concentration values for several consecutive days in the area. The influence of meteorological conditions on the air pollution episode registered between February 24 and March 05, 2003 was assessed through numerical simulations with the SPM-BRAMS model. Observational studies show that the occurrence of calm winds, especially during the night and morning, favor the formation of high ozone concentration values over the region. The penetration time and the influence of the sea breeze are essential for the transport of ozone and its precursors. These conditions were well simulated by the model. For the most critical days, when several monitoring stations recorded the occurrence of violations to the ozone National Air Quality Standard, the model simulated properly the atmospheric conditions needed for the maintenance of high ozone concentration values, without any artificial procedure during the integrations.

ASPECTOS OBSERVACIONAIS DA ILHA DE CALOR EM SANTIAGO DO CHILE

The behavior of the temperature for the year of 2004 was analyzedfor six chileans meteorological stations situated inside and outside ofthe Santiago. The results showed that the stations situated inside thecity has bigger temperature than the stations situated outside of the city.In the winter time, the difference between the stations situated inside ofthe city shows that the center is hotter, while the difference of temperaturebetween the stations in the limits of the town and outside the townshows that the temperature is bigger than the non-urban stations. In thesummer, the city is always hotter.

EFFECTS OF SIZE DISTRIBUTIONS FROM TWO DISTINCT POLLUTED ENVIRONMENTS ON DRY DEPOSITION OF ATMOSPHERIC AEROSOLS

Resumo Um modelo matematico simples foi utilizado para estudar o efeito da distribuicao de tamanho das particulas sobre a eficiencia de remocao por deposicao seca. Para esta finalidade foram utilizadas duas distribuicoes de tamanho de aerossois, tipicas de ambientes poluidos: uma distribuicao de ambiente de queimada (Amazonia) e outra de ambiente urbano (Sao Paulo). Os resultados mostraram que particulas originarias de ambiente urbano sao mais eficientemente removidas por deposicao seca do que particulas de queimada. Este comportamento esta associado ao fato de que a natureza de remocao das particulas por deposicao seca e pouco eficiente para diâmetros entre 0,1 e 1,0 mm, dominio em que se concentra a maior parte das particulas de queimada. Esse mecanismo diferencial de deposicao e o que explica o maior efeito deleterio das particulas ultra-finas no sistema respiratorio humano.

PARTICULATE MATTER CONCENTRATION FORECAST OVER THE METROPOLITAN AREA OF SÃO PAULO

Em virtude dos grandes males causados a saude pela poluicao nosgrandes centros urbanos, a utilizacao de modelos meteorologicos acopladosaos modelos quimicos, resultando em modelos de previsao da qualidade doar, tem aumentado significativamente nos ultimos anos. Exemplos dessetipo de utilizacao sao os modelos WRF-CHEM, utilizado em varios paisesdo mundo, e SPM-BRAMS, recentemente desenvolvido por pesquisadoresda Universidade de Sao Paulo e do INPE e utilizado operacionalmente nolaboratorio MASTER do IAG-USP. Embora o modelo seja utilizado para aprevisao das concentracoes dos principais poluentes monitorados na regiao, neste trabalho sao apresentadas comparacoes entre as concentracoesde material particulado fino (PM2.5) previstas e aquelas derivadas das observacoes na rede da CETESB. O PM2.5 esta relacionado aos efeitos deleteriosa saude e esta sendo estudado o estabelecimento de um padrao de qualidadedo ar para esse poluente. Alem da questao da relacao com impactosnegativos a saude, ha tambem os impactos ao clima, ja que as particulasfinas estao relacionadas com a formacao de precipitacao e extincao da radiacao.

AVALIAÇÃO DOS RESULTADOS DE CONCENTRAÇÃO DE OZÔNIO TROPOSFÉRICO SIMULADOS PELO MODELO SPM-BRAMS SOBRE A RMSP

Avaliacao dos resultados de concentracao de ozoniotroposferico simulados pelo modeloSPM-BRAMS sobre a RMSP