Jornalismo e ciência na universidade

Prefácio de Marcelo KnobelConhecimentos científicos produzidos na universidade chegam até a comunidade? Pesquisadores e jornalistas conseguem dialogar? Como a linguagem jornalística traduz a ciência para o leigo? Qual o papel das imagens na divulgação científica? Essas são algumas perguntas que os artigos que compõem este livro procuram responder. São relatadas experiências desenvolvidas por professores e estudantes das áreas de comunicação e educação da Universidade Federal de Uberlândia em projetos sobre comunicação pública e popularização da ciência que produziram o jornal impresso “Ciência em Pauta”, o programa de rádio “Ciência no Ar”, o programa de TV “Minuto Ciência UFU” e o blog “ImunoCast”.Com revisões bibliográficas, análises midiáticas e relatos de trabalhos, este livro é uma coletânea de reflexões e vivências sobre a ponte edificada – ou não – entre a ciência e a sociedade por meio da comunicação

Biogenic and biomass burning aerosol optical

Foram analisadas as principais propriedades ópticas do aerossol atmosférico a partir dos radiômetros da rede NASA/AERONET em três regiões de interesse: o Norte da Amazônia, a região do arco do desflorestamento, e a região do cerrado. A metodologia envolveu a obtenção da espessura óptica do aerossol (), distribuição de tamanho, albedo de espalhamento único (0), e outras propriedades com o uso de radiômetros CIMEL operados pela rede de fotômetros NASA/AERONET. Foram determinadas propriedades ópticas de aerossóis biogênicos naturais, bem como das emissões de queimadas. Observaram-se profundas modificações nas propriedades do aerossol durante a estação seca, como decorrência de emissões de queimadas. A profundidade óptica do aerossol, 500nm, aumentou de um valor de background de 0,15±0,13 durante a estação chuvosa, para valores médios diários da ordem de 2,5 a 3,5, o que indica uma atmosfera extremamente carregada de aerossóis na região do arco do desflorestamento. O coeficiente de Ångström, que expressa o tamanho das partículas, aumentou significativamente durante a estação de queimadas para altos valores de , indicando a predominância de partículas finas nessa época do ano, aumento esse que também é visto no volume da moda fina da distribuição de tamanho na região do arco do desflorestamento, com um pico no raio de 0,15 m. O aerossol biogênico natural está presente durante todo o ano, em todos os locais analisados. da região Amazônica. O aerossol produzido secundariamente na atmosfera, pela oxidação de compostos emitidos pela vegetação, contribui para o volume da moda fina, enquanto que as partículas primárias emitidas pela floresta contribuem para a moda grossa. Das propriedades intrínsecas do aerossol, observou-se que o albedo de espalhamento único do aerossol (0) tem valor médio de 0,920,03 nas estações do arco do desflorestamento. Em Cuiabá foi possível observar duas modas de valores de 0, uma correspondente ao aerossol natural do cerrado com valor de 0,84±0,05, e outra correspondente a queimadas de longa distância com valor de 0,92±0,03, compatível com as estações do arco do desflorestamento. O Norte da Amazônia foi caracterizado por aerossol extremamente espalhador, com albedo de 0,98±0,01 durante a estação chuvosa em Balbina. O impacto climático dos aerossóis foi quantificado através das inversões de forçante radiativa direta do aerossol da AERONET. A forçante radiativa instantânea no topo da atmosfera chegou a -100 W.m-2 na região do arco de desflorestamento. O valor de eficiência de forçante do aerossol na Amazônia variou entre 38,6 W.m-2.-1, em Alta Floresta, a 50,9 W.m-2.-1 em Belterra. Foi também realizada uma análise entre as medidas integradas na coluna atmosférica com medidas de concentração de aerossóis ao nível do solo. Nesse intuito, estudou-se a relação da profundidade óptica do aerossol obtida pelos radiômetros da AERONET e a concentração de material particulado fino, MP2,5 obtida ao nível do solo. A regressão linear encontrada foi de MP2,5 = (37±2)500 + (5±2) em unidades de [g.m-3] para a região do arco do desflorestamento, e MP2,5 = (30,7±1,3)500 + (0,08±0,40) nas mesmas unidades, para a região de Belterra. A validação feita com obtido independentemente pelo sensor MODIS mostrou que a relação é adequada para o arco do desflorestamento e a profundidade óptica do aerossol obtida por ambos os métodos pode ser usada alternativamente para estudos de efeitos de material particulado na saúde humana.This work has analyzed the main optical properties of atmospheric aerosol particles in three regions of interest: the Northern Amazon region, the arc of deforestation and the Brazilian cerrado. The methodology involved the measurement of aerosol optical thickness (), size distribution, single scattering albedo (0), and other properties with the use of CIMEL radiometers that are part of a sun-photometer network operated by AERONET/NASA. It was determined the optical properties of natural biogenic aerosols as well as emissions from biomass burning. We observed large changes in the physical properties of aerosols during the dry season, as a result of emissions from fires. The aerosol optical depth at 500nm, 500nm increased from a background value of 0.15 ± 0.13 during the wet season for the daily average values of 2.5 to 3.5, indicating a highly loaded atmosphere in the region of the arc of deforestation. The Ångström coefficient, which indicates the particle size, increased significantly during the burning season for high values of , indicating the predominance of fine particles in this season. This increase due to biomass burning is also observed in the volume size distribution, with a large peak centered at a radius of 0.15 m. The natural biogenic aerosol is present throughout the year in all locations studied in the Amazon region with similar properties. The secondary organic aerosol produced in the atmosphere by oxidation of compounds emitted by the vegetation contributes to the volume of fine mode, while the primary particles emitted by the forest contribute to the coarse mode. The intrinsic properties of the aerosol were also analyzed. It was observed that the single scattering albedo of the aerosol (0) has an average value of 0.92 0.03 in the stations close to the region of the arc of deforestation. In Cuiabá it was possible to observe two modes in the distribution of 0, corresponding to a natural aerosol from the cerrado with an average value of 0.84 ± 0.05, and other mode corresponding to fires from long range transport with a relatively high value of 0.92 ± 0.03, consistent with the measurements at the arc of deforestation. The northern Amazon region was characterized by extremely scattering aerosols with albedo of 0.98 ± 0.01 during the rainy season in Balbina. The climate impact of aerosols was characterized by aerosol direct radiative forcing from inversions calculations by AERONET. The instantaneous radiative forcing at the top of the atmosphere reached a very high -100 Wm-2 in the region of the arc of deforestation. The value of the aerosol forcing efficiency in the Amazon ranged from -38.6 Wm-2.-1 in Alta Floresta, to -50.9 Wm-2.-1 in Belterra, compatible with measurements using other methods. This work also has done an analysis of the comparison between 500nm column measurements from AERONET and ground based aerosol concentrations. It was studied in detail the relationship of the aerosol optical depth obtained by the AERONET radiometers with the concentration of fine particulate matter, PM2.5 obtained at ground level in several sites in Amazonia. We found a statistically significant correlation and it was derived a linear regression of PM2.5 = (37±2) AOD500 + (5±2) in g/m³ in the region of the deforestation arc calculated from data in the period of 2001-2006. In addition, estimates from MODIS aerosol optical depth was used to calculate ground based PM2.5 concentrations, with statistically significant agreement. This technique is very useful to assess health effects of aerosols in Amazonia

Aerosol Particles in Amazonia: Their Composition, Role in the Radiation Balance, Cloud Formation, and Nutrient Cycles

The atmosphere above tropical forests plays a very active part in the biogeochemical cycles that are critically important for the processes that maintain the ecosystem, including processes involving the vegetation, soil, hydrology, and atmospheric composition. Aerosol particles control key ingredients of the climatic and ecological environment in Amazonia. The radiative balance is strongly influenced by the direct and indirect radiative forcing of aerosol particles. Nutrient cycling is partially controlled by dry and wet deposition of key plant nutrients. It was observed that the aerosol particles that act as cloud condensation nuclei influence cloud formation and dynamics, having the potential to change precipitation regimes over Amazonia. The 10-year-long record of aerosol optical thickness measurements in Amazonia shows a strongly negative radiative forcing of -37 W m-2 averaged over 7 years of dry season measurements in Alta Floresta. There is a strong influence of biomass-burning aerosols on the cloud microphysical properties during the dry season. The connections between the amount of aerosol particles and carbon uptake trough photosynthesis highlighted the close connection between forest natural processes and the aerosol loading in the atmosphere. Climate change combined with socioeconomic drivers could alter significantly the emission of trace gases, aerosols, and water vapor fluxes from the forest to the atmosphere. It is a vital task to quickly reduce Amazonian deforestation rates, and to implement solid and long-term conservation policies in Amazonia. © 2009 by the American Geophysical Union. All rights reserved

Aerosol particles in Amazonia: Their composition, role in the radiation balance, cloud formation, and nutrient cycles

The atmosphere above tropical forests plays a very active part in the biogeochemical cycles that are critically important for the processes that maintain the ecosystem, including processes involving the vegetation, soil, hydrology, and atmospheric composition. Aerosol particles control key ingredients of the climatic and ecological environment in Amazonia. The radiative balance is strongly influenced by the direct and indirect radiative forcing of aerosol particles. Nutrient cycling is partially controlled by dry and wet deposition of key plant nutrients. It was observed that the aerosol particles that act as cloud condensation nuclei influence cloud formation and dynamics, having the potential to change precipitation regimes over Amazonia. The 10-year-long record of aerosol optical thickness measurements in Amazonia shows a strongly negative radiative forcing of -37 W m-2 averaged over 7 years of dry season measurements in Alta Floresta. There is a strong influence of biomass-burning aerosols on the cloud microphysical properties during the dry season. The connections between the amount of aerosol particles and carbon uptake trough photosynthesis highlighted the close connection between forest natural processes and the aerosol loading in the atmosphere. Climate change combined with socioeconomic drivers could alter significantly the emission of trace gases, aerosols, and water vapor fluxes from the forest to the atmosphere. It is a vital task to quickly reduce Amazonian deforestation rates, and to implement solid and long-term conservation policies in Amazonia. © Copyright 2009 by the American Geophysical Union