GEOS-S2S Version 2: The GMAO High Resolution Coupled Model and Assimilation System for Seasonal Prediction.

The Global Modeling and Assimilation Office (GMAO) has recently released a new version of the Goddard Earth Observing System (GEOS) Sub-seasonal to Seasonal prediction (S2S) system, GEOS-S2S-2, that represents a substantial improvement in performance and infrastructure over the previous system. The system is described here in detail, and results are presented from forecasts, climate equillibrium simulations and data assimilation experiments. The climate or equillibrium state of the atmosphere and ocean showed a substantial reduction in bias relative to GEOS-S2S-1. The GEOS-S2S-2 coupled reanalysis also showed substantial improvements, attributed to the assimilation of along-track Absolute Dynamic Topography. The forecast skill on subseasonal scales showed a much-improved prediction of the Madden-Julian Oscillation in GEOS-S2S-2, and on a seasonal scale the tropical Pacific forecasts show substantial improvement in the east and comparable skill to GEOS-S2S-1 in the central Pacific. GEOS-S2S-2 anomaly correlations of both land surface temperature and precipitation were comparable to GEOS-S2S-1, and showed substantially reduced root mean square error of surface temperature. The remaining issues described here are being addressed in the development of GEOS-S2S Version 3, and with that system GMAO will continue its tradition of maintaining a state of the art seasonal prediction system for use in evaluating the impact on seasonal and decadal forecasts of assimilating newly available satellite observations, as well as to evaluate additional sources of predictability in the earth system through the expanded coupling of the earth system model and assimilation components.

Observations of sesquiterpenes and their oxidation products in central Amazonia during the wet and dry seasons.

Biogenic volatile organic compounds (BVOCs) from the Amazon forest region represent the largest source of organic carbon emissions to the atmosphere globally. These BVOC emissions dominantly consist of volatile and intermediate-volatility terpenoid compounds that undergo chemical transformations in the atmosphere to form oxygenated condensable gases and secondary organic aerosol (SOA). We collected quartz filter samples with 12 h time resolution and performed hourly in situ measurements with a semi-volatile thermal desorption aerosol gas chromatograph (SV-TAG) at a rural site ("T3") located to the west of the urban center of Manaus, Brazil as part of the Green Ocean Amazon (GoAmazon2014/5) field campaign to measure intermediate-volatility and semi-volatile BVOCs and their oxidation products during the wet and dry seasons. We speciated and quantified 30 sesquiterpenes and 4 diterpenes with mean concentrations in the range 0.01-6.04 ngm-3 (1-670ppqv). We estimate that sesquiterpenes contribute approximately 14 and 12% to the total reactive loss of O3 via reaction with isoprene or terpenes during the wet and dry seasons, respectively. This is reduced from ~ 50-70 % for within-canopy reactive O3 loss attributed to the ozonolysis of highly reactive sesquiterpenes (e.g., ß-caryophyllene) that are reacted away before reaching our measurement site. We further identify a suite of their oxidation products in the gas and particle phases and explore their role in biogenic SOA formation in the central Amazon region. Synthesized authentic standards were also used to quantify gas- and particle-phase oxidation products derived from ß-caryophyllene. Using tracer-based scaling methods for these products, we roughly estimate that sesquiterpene oxidation contributes at least 0.4-5 % (median 1 %) of total submicron OA mass. However, this is likely a low-end estimate, as evidence for additional unaccounted sesquiterpenes and their oxidation products clearly exists. By comparing our field data to laboratory-based sesquiterpene oxidation experiments we confirm that more than 40 additional observed compounds produced through sesquiterpene oxidation are present in Amazonian SOA, warranting further efforts towards more complete quantification.

Airborne observations reveal elevational gradient in tropical forest isoprene emissions.

Isoprene dominates global non-methane volatile organic compound emissions, and impacts tropospheric chemistry by influencing oxidants and aerosols. Isoprene emission rates vary over several orders of magnitude for different plants, and characterizing this immense biological chemodiversity is a challenge for estimating isoprene emission from tropical forests. Here we present the isoprene emission estimates from aircraft eddy covariance measurements over the Amazonian forest. We report isoprene emission rates that are three times higher than satellite top-down estimates and 35% higher than model predictions. The results reveal strong correlations between observed isoprene emission rates and terrain elevations, which are confirmed by similar correlations between satellite-derived isoprene emissions and terrain elevations. We propose that the elevational gradient in the Amazonian forest isoprene emission capacity is determined by plant species distributions and can substantially explain isoprene emission variability in tropical forests, and use a model to demonstrate the resulting impacts on regional air quality.

Modeling the radiative effects of biomass burning aerosols on carbon fluxes in the Amazon region.

Every year, a dense smoke haze covers a large portion of South America originating from fires in the Amazon Basin and central parts of Brazil during the dry biomass burning season between August and October. Over a large portion of South America, the average aerosol optical depth at 550 nm exceeds 1.0 during the fire season, while the background value during the rainy season is below 0.2. Biomass burning aerosol particles increase scattering and absorption of the incident solar radiation. The regional-scale aerosol layer reduces the amount of solar energy reaching the surface, cools the near-surface air, and increases the diffuse radiation fraction over a large disturbed area of the Amazon rainforest. These factors affect the energy and CO2 fluxes at the surface. In this work, we applied a fully integrated atmospheric model to assess the impact of biomass burning aerosols in CO2 fluxes in the Amazon region during 2010. We address the effects of the attenuation of global solar radiation and the enhancement of the diffuse solar radiation flux inside the vegetation canopy. Our results indicate that biomass burning aerosols led to increases of about 27% in the gross primary productivity of Amazonia and 10% in plant respiration as well as a decline in soil respiration of 3%. Consequently, in our model Amazonia became a net carbon sink; net ecosystem exchange during September 2010 dropped from +101 to -104 TgC when the aerosol effects are considered, mainly due to the aerosol diffuse radiation effect. For the forest biome, our results point to a dominance of the diffuse radiation effect on CO2 fluxes, reaching a balance of 50-50% between the diffuse and direct aerosol effects for high aerosol loads. For C3 grasses and savanna (cerrado), as expected, the contribution of the diffuse radiation effect is much lower, tending to zero with the increase in aerosol load. Taking all biomes together, our model shows the Amazon during the dry season, in the presence of high biomass burning aerosol loads, changing from being a source to being a sink of CO2 to the atmosphere.

The Brazilian developments on the Regional Atmospheric Modeling System (BRAMS 5.2): an integrated environmental model tuned for tropical areas.

We present a new version of the Brazilian developments on the Regional Atmospheric Modeling System where different previous versions for weather, chemistry and carbon cycle were unified in a single integrated software system. The new version also has a new set of state-of-the-art physical parameterizations and greater computational parallel and memory usage efficiency. Together with the description of the main features are examples of the quality of the transport scheme for scalars, radiative fluxes on surface and model simulation of rainfall systems over South America in different spatial resolutions using a scale-aware convective parameterization. Besides, the simulation of the diurnal cycle of the convection and carbon dioxide concentration over the Amazon Basin, as well as carbon dioxide fluxes from biogenic processes over a large portion of South America are shown. Atmospheric chemistry examples present model performance in simulating near-surface carbon monoxide and ozone in Amazon Basin and Rio de Janeiro megacity. For tracer transport and dispersion, it is demonstrated the model capabilities to simulate the volcanic ash 3-d redistribution associated with the eruption of a Chilean volcano. Then, the gain of computational efficiency is described with some details. BRAMS has been applied for research and operational forecasting mainly in South America. Model results from the operational weather forecast of BRAMS on 5 km grid spacing in the Center for Weather Forecasting and Climate Studies, INPE/Brazil, since 2013 are used to quantify the model skill of near surface variables and rainfall. The scores show the reliability of BRAMS for the tropical and subtropical areas of South America. Requirements for keeping this modeling system competitive regarding on its functionalities and skills are discussed. At last, we highlight the relevant contribution of this work on the building up of a South American community of model developers.

Air Quality and Health Impacts of Future Ethanol Production and Use in São Paulo State, Brazil.

It is often argued that liquid biofuels are cleaner than fossil fuels, and therefore better for human health, however, the evidence on this issue is still unclear. Brazil's high uptake of ethanol and role as a major producer makes it the most appropriate case study to assess the merits of different biofuel policies. Accordingly, we modeled the impact on air quality and health of two future fuel scenarios in São Paulo State: a business-as-usual scenario where ethanol production and use proceeds according to government predictions and a counterfactual scenario where ethanol is frozen at 2010 levels and future transport fuel demand is met with gasoline. The population-weighted exposure to fine particulate matter (PM2.5) and ozone was 3.0 µg/m³ and 0.3 ppb lower, respectively, in 2020 in the scenario emphasizing gasoline compared with the business-as-usual (ethanol) scenario. The lower exposure to both pollutants in the gasoline scenario would result in the population living 1100 additional life-years in the first year, and if sustained, would increase to 40,000 life-years in year 20 and continue to rise. Without additional measures to limit emissions, increasing the use of ethanol in Brazil could lead to higher air pollution-related population health burdens when compared to policy that prioritizes gasoline.

Air pollution and hospital admissions for respiratory diseases in the subequatorial Amazon: a time series approach.

The objective of the study is to evaluate the effect of the daily variation in concentrations of fine particulate matter (diameter less than 2.5 microm--PM2.5) resulting from the burning of biomass on the daily number of hospitalizations of children and elderly people for respiratory diseases, in Alta Floresta and Tangará da Serra in the Brazilian Amazon in 2005. This is an ecological time series study that uses data on daily number of hospitalizations of children and the elderly for respiratory diseases, and estimated concentration of PM2.5. In Alta Floresta, the percentage increases in the relative risk (%RR) of hospitalization for respiratory diseases in children were significant for the whole year and for the dry season with 3-4 day lags. In the dry season these measurements reach 6% (95%CI: 1.4-10.8). The associations were significant for moving averages of 3-5 days. The %RR for the elderly was significant for the current day of the drought, with a 6.8% increase (95%CI: 0.5-13.5) for each additional 10 microg/m3 of PM2.5. No associations were verified for Tangará da Serra. The PM2.5 from the burning of biomass increased hospitalizations for respiratory diseases in children and the elderly.

Material particulado (PM2.5) de queima de biomassa e doenças respiratórias no sul da Amazônia brasileira / Particulate matter (PM2.5) of biomass burning emissions and respiratory diseases in the south of the Brazilian Amazon

OBJETIVOS: Analisar espacialmente o efeito da exposição ao material particulado (PM2.5) na ocorrência de doenças do aparelho respiratório de crianças de um a quatro anos e de idosos com sessenta e cinco anos ou mais nos municípios do Estado de Mato Grosso em 2004. MÉTODOS: Trata-se de um estudo ecológico em duas etapas. A primeira foi uma investigação da autocorrelação espacial global da prevalência de internações por doenças respiratórias e do percentual de horas críticas de concentração do material particulado nos municípios do estado de Mato Grosso, empregando-se o método bayesiano empírico para minimização das flutuações aleatórias dos indicadores e a estatística Moran "global". A segunda, uma regressão múltipla espacial, teve como variáveis resposta a prevalência de internações por doenças respiratórias, e como variável de exposição o percentual de horas críticas anuais. Para ajuste, foram utilizadas variáveis proxies de poluição do ar, variáveis de atenção à saúde e de condições de vida da população. RESULTADOS: Não foram observados padrões espaciais globais de prevalência de doenças respiratórias em grupos sensíveis nos municípios, mas evidenciou-se elevada dependência espacial do percentual de horas críticas anuais de concentração do material particulado. Na regressão múltipla, foram observadas associações estatisticamente significativas entre a prevalência de internações por doenças respiratórias e o percentual de horas críticas anuais de material particulado. CONCLUSÕES: As emissões de material particulado originadas de queimadas na Amazônia Legal estão relacionadas à prevalência de internações por doenças respiratórias em grupos populacionais sensíveis nos municípios do Estado de Mato Grosso.

Air pollution and hospital admissions for respiratory diseases in the subequatorial Amazon: a time series approach / Poluição do ar e admissões hospitalares por doenças respiratórias na Amazônia subequatorial: abordagem de séries temporais

The objective of the study is to evaluate the effect of the daily variation in concentrations of fine particulate matter (diameter less than 2.5µm - PM2.5) resulting from the burning of biomass on the daily number of hospitalizations of children and elderly people for respiratory diseases, in Alta Floresta and Tangará da Serra in the Brazilian Amazon in 2005. This is an ecological time series study that uses data on daily number of hospitalizations of children and the elderly for respiratory diseases, and estimated concentration of PM2.5. In Alta Floresta, the percentage increases in the relative risk ( percentRR) of hospitalization for respiratory diseases in children were significant for the whole year and for the dry season with 3-4 day lags. In the dry season these measurements reach 6 percent (95 percentCI: 1.4-10.8). The associations were sig-nificant for moving averages of 3-5 days. The percentRR for the elderly was significant for the current day of the drought, with a 6.8 percent increase (95 percentCI: 0.5-13.5) for each additional 10µg/m3 of PM2.5. No as-sociations were verified for Tangara da Serra. The PM2.5 from the burning of biomass increased hospitalizations for respiratory diseases in children and the elderly.

Avaliar o efeito da variação diária nas concentrações de PM2.5 da queima de biomassa sobre o número diário de hospitalizações de crianças e idosos por doenças respiratórias, em Alta Floresta e Tangará da Serra, Amazônia brasileira, em 2005. Estudo ecológico de séries temporais de hospitalizações por doenças respiratórias de crianças e de idosos, estimativas de concentrações diárias de PM2.5, variáveis meteorológicas e de calendário. Para Alta Floresta os aumentos percentuais do risco relativo ( por centoRR) de internações por doenças respiratórias em crianças foram significantes para o ano todo e para o período de seca, com defasagens de 3-4 dias. No período de seca o incremento é de 6 por cento (IC95 por cento: 1,4-10,8). Para médias móveis de 3-5 dias as associações mostraram-se significantes. O por centoRR para idosos foram significantes para o dia corrente na seca com 6,8 por cento (IC95 por cento: 0,5-13,5) de incremento para aumento de 10µg/m³ de PM2.5. Não foram verificadas associações para Tangara da Serra. As emissões de PM2.5 pela queima de biomassa na Amazônia aumentaram as hospitalizações por doenças respiratórias de crianças e idosos.

[Association between particulate matter from biomass burning and respiratory diseases in the southern region of the Brazilian Amazon]. / Associação entre material particulado de queimadas e doenças respiratórias na região sul da Amazônia brasileira.

OBJECTIVE: To investigate the short-term effects of exposure to particulate matter from biomass burning in the Amazon on the daily demand for outpatient care due to respiratory diseases in children and the elderly. METHODS: Epidemiologic study with ecologic time series design. Daily consultation records were obtained from the 14 primary health care clinics in the municipality of Alta Floresta, state of Mato Grosso, in the southern region of the Brazilian Amazon, between January 2004 and December 2005. Information on the daily levels of fine particulate matter was made available by the Brazilian National Institute for Spatial Research. To control for confounding factors (situations in which a non-causal association between exposure and disease is observed due to a third variable), variables related to time trends, seasonality, temperature, relative humidity, rainfall, and calendar effects (such as occurrence of holidays and weekends) were included in the model. Poisson regression with generalized additive models was used. RESULTS: A 10 microg/m3 increase in the level of exposure to particulate matter was associated with increases of 2.9% and 2.6% in outpatient consultations due to respiratory diseases in children on the 6th and 7th days following exposure. Significant associations were not observed for elderly individuals. CONCLUSIONS: The results suggest that the levels of particulate matter from biomass burning in the Amazon are associated with adverse effects on the respiratory health of children.

Impact on human health of particulate matter emitted from burnings in the Brazilian Amazon region.

OBJECTIVE: To analyze the impact on human health of exposure to particulate matter emitted from burnings in the Brazilian Amazon region. METHODS: This was an ecological study using an environmental exposure indicator presented as the percentage of annual hours (AH%) of PM2.5 above 80 microg/m3. The outcome variables were the rates of hospitalization due to respiratory disease among children, the elderly and the intermediate age group, and due to childbirth. Data were obtained from the National Space Research Institute and the Ministry of Health for all of the microregions of the Brazilian Amazon region, for the years 2004 and 2005. Multiple regression models for the outcome variables in relation to the predictive variable AH% of PM2.5 above 80 microg/m3 were analyzed. The Human Development Index (HDI) and mean number of complete blood counts per 100 inhabitants in the Brazilian Amazon region were the control variables in the regression analyses. RESULTS: The association of the exposure indicator (AH%) was higher for the elderly than for other age groups (beta = 0.10). For each 1% increase in the exposure indicator there was an increase of 8% in child hospitalization, 10% in hospitalization of the elderly, and 5% for the intermediate age group, even after controlling for HDI and mean number of complete blood counts. No association was found between the AH% and hospitalization due to childbirth. CONCLUSIONS: The indicator of atmospheric pollution showed an association with occurrences of respiratory diseases in the Brazilian Amazon region, especially in the more vulnerable age groups. This indicator may be used to assess the effects of forest burning on human health.

Impact on human health of particulate matter emitted from burnings in the Brazilian Amazon region / Impactos na saúde humana de partículas emitidas por queimadas na Amazônia brasileira

OBJECTIVE: To analyze the impact on human health of exposure to particulate matter emitted from burnings in the Brazilian Amazon region. METHODS: This was an ecological study using an environmental exposure indicator presented as the percentage of annual hours (AH percent) of PM2.5 above 80 μg/m3. The outcome variables were the rates of hospitalization due to respiratory disease among children, the elderly and the intermediate age group, and due to childbirth. Data were obtained from the National Space Research Institute and the Ministry of Health for all of the microregions of the Brazilian Amazon region, for the years 2004 and 2005. Multiple regression models for the outcome variables in relation to the predictive variable AH percent of PM2.5 above 80 μg/m3 were analyzed. The Human Development Index (HDI) and mean number of complete blood counts per 100 inhabitants in the Brazilian Amazon region were the control variables in the regression analyses. RESULTS: The association of the exposure indicator (AH percent) was higher for the elderly than for other age groups (β = 0.10). For each 1 percent increase in the exposure indicator there was an increase of 8 percent in child hospitalization, 10 percent in hospitalization of the elderly, and 5 percent for the intermediate age group, even after controlling for HDI and mean number of complete blood counts. No association was found between the AH percent and hospitalization due to childbirth. CONCLUSIONS: The indicator of atmospheric pollution showed an association with occurrences of respiratory diseases in the Brazilian Amazon region, especially in the more vulnerable age groups. This indicator may be used to assess the effects of forest burning on human health.

OBJETIVO: Analisar o impacto à saúde humana pela exposição ao material particulado das emissões de queimadas na Amazônia brasileira. MÉTODOS: Estudo ecológico utilizando o indicador de exposição ambiental apresentado como percentagem anual de horas (AH por cento) de PM2,5 acima de 80 μg/m³ e como desfecho taxas de hospitalização por doenças respiratórias em crianças, idosos e grupos etários intermediários e taxas de hospitalização por parto. Os dados foram obtidos do Instituto Nacional de Pesquisas Espaciais e do Ministério da Saúde para todas as microrregiões da Amazônia Brasileira, nos anos 2004 e 2005. Foram analisados modelos de regressão múltipla das variáveis de desfecho com a variável preditora AH por cento acima de 80 μg/m³ para PM2,5. O Índice de Desenvolvimento Humano (IDH) e o número médio de hemogramas por 100 habitantes na região da Amazônia brasileira foram variáveis de controle nas análises de regressão. RESULTADOS: Observou-se maior associação do indicador de exposição (AH por cento) para os idosos do que para outros grupos etários (β = 0,10). Para cada ponto percentual de aumento no indicador de exposição, houve aumento de 10 por cento na taxa de hospitalização de idosos, 8 por cento em internações de crianças, e 5 por cento para a faixa etária intermediária, mesmo ajustando por IDH e número médio de hemogramas. Não foi encontrada associação entre AH por cento e a taxa de hospitalização por parto. CONCLUSÕES: O indicador de poluição atmosférica mostrou associação com a ocorrência de doenças respiratórias, em especial nos grupos etários mais vulneráveis da Amazônia brasileira, podendo ser utilizado na abordagem dos efeitos da queima das florestas na saúde humana.

Associação entre material particulado de queimadas e doenças respiratórias na região sul da Amazônia brasileira / Association between particulate matter from biomass burning and respiratory diseases in the southern region of the Brazilian Amazon

OBJETIVO: Investigar os efeitos de curto prazo da exposição ao material particulado de queimadas da Amazônia na demanda diária de atendimento ambulatorial por doenças respiratórias de crianças e de idosos. MÉTODOS: Estudo epidemiológico com delineamento ecológico de séries temporais. Os registros diários de atendimento ambulatorial foram obtidos nas 14 unidades de saúde do município de Alta Floresta, Mato Grosso, região sul da Amazônia brasileira, no período de janeiro de 2004 a dezembro de 2005. Informação sobre os níveis diários de material particulado fino foi disponibilizada pelo Instituto Nacional de Pesquisas Espaciais. Para controlar possíveis fatores de confusão (situações nas quais uma associação não causal entre exposição e doença é observada devido a uma terceira variável), foram adicionadas ao modelo variáveis referentes a tendência temporal, sazonalidade, temperatura, umidade relativa do ar, precipitação pluviométrica e efeitos de calendário (como ocorrência de feriados e finais de semana). Utilizou-se regressão de Poisson via modelos aditivos generalizados. RESULTADOS: Um incremento de 10 µg/m³ nos níveis de exposição ao material particulado esteve associado a aumentos de 2,9 e 2,6 por cento nos atendimentos ambulatoriais por doenças respiratórias de crianças no 6º e 7º dias subsequentes à exposição. Não foram encontradas associações significativas nos atendimentos de idosos. CONCLUSÕES: Os resultados sugerem que os níveis de material particulado das queimadas na Amazônia estão associados a efeitos adversos à saúde respiratória de crianças.

OBJECTIVE: To investigate the short-term effects of exposure to particulate matter from biomass burning in the Amazon on the daily demand for outpatient care due to respiratory diseases in children and the elderly. METHODS: Epidemiologic study with ecologic time series design. Daily consultation records were obtained from the 14 primary health care clinics in the municipality of Alta Floresta, state of Mato Grosso, in the southern region of the Brazilian Amazon, between January 2004 and December 2005. Information on the daily levels of fine particulate matter was made available by the Brazilian National Institute for Spatial Research. To control for confounding factors (situations in which a non-causal association between exposure and disease is observed due to a third variable), variables related to time trends, seasonality, temperature, relative humidity, rainfall, and calendar effects (such as occurrence of holidays and weekends) were included in the model. Poisson regression with generalized additive models was used. RESULTS: A 10 μg/m³ increase in the level of exposure to particulate matter was associated with increases of 2.9 percent and 2.6 percent in outpatient consultations due to respiratory diseases in children on the 6th and 7th days following exposure. Significant associations were not observed for elderly individuals. CONCLUSIONS: The results suggest that the levels of particulate matter from biomass burning in the Amazon are associated with adverse effects on the respiratory health of children.

Química atmosférica na Amazônia: a floresta e as emissões de queimadas controlando a composição da atmosfera amazônica / Atmospheric chemistry in Amazonia: the forest and the biomass burning emissions controlling the composition of the Amazonian atmosphere

Entender os processos naturais que regulam a composição da atmosfera é crítico para que se possa desenvolver uma estratégia de desenvolvimento sustentável na região. As grandes emissões de gases e partículas durante a estação seca provenientes das queimadas alteram profundamente a composição da atmosfera amazônica na maior parte de sua área. As concentrações de partículas de aerossóis e gases traço aumentam por fatores de 2 a 8 em grandes áreas, afetando os mecanismos naturais de uma série de processos atmosféricos na região amazônica. Os mecanismos de formação de nuvens, por exemplo, são profundamente alterados quando a concentração de núcleos de condensação de nuvens (NCN) passa de 200 a 300 NCN/cm³ na estação chuvosa para 5.000-10.000 NCN/centímetro cúbico na estação seca. As gotas de nuvens sofrem uma redução de tamanho de 18 a 25 micrômetros para 5 a 10 micrômetros, diminuindo a eficiência do processo de precipitação e suprimindo a formação de nuvens. A concentração de ozônio, um gás importante para a saúde da floresta amazônica passa de cerca de 12 partes por bilhão em volume (ppb) (concentração típica ao meio do dia na estação chuvosa) para valores em regiões fortemente impactadas por queimadas de até 100 ppb, nível que pode ser fitotóxico para a vegetação. O balanço de radiação é fortemente afetado, com uma perda líquida de até 70 por cento da radiação fotossinteticamente ativa na superfície.

Emissões de queimadas em ecossistemas da América do Sul / Emissões de queimadas em ecossistemas da América do Sul

As queimadas que ocorrem majoritariamente em áreas tropicais do planeta, são fontes importantes de poluentes para a atmosfera. Na América do Sul, durante os meses de inverno, uma área, principalmente de ecossistemas de cerrado e floresta, da ordem de 40 mil km² é queimada anualmente. Estas queimadas ocorrem primariamente nas regiões Amazônica e do Brasil Central, porém, através do transporte atmosférico de suas emissões resulta uma distribuição espacial de fumaça sobre uma extensa área, ao redor de 4-5 milhões de km², em muito superior a área onde estão concentradas as queimadas. Durante a combustão de biomassa são emitidos para a atmosfera gases poluentes e partículas de aerossol que interagem eficientemente com a radiação solar e afetam os processos de microfísica e dinâmica de formação de nuvens e a qualidade do ar. Os efeitos destas emissões excedem, portanto, a escala local e afetam regionalmente a composição e propriedades físicas e químicas da atmosfera na América do Sul e áreas oceânicas vizinhas, com potencial impacto em escala global.