307 research outputs found

    Mudanças climáticas e o Brasil

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    Oportunidades e vulnerabilidades do Brasil nas questões do clima e da sustentabilidade

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    As mudanças climáticas constituem um dos maiores desafios da humanidade hoje. É urgente entendermos como os ecossistemas brasileiros, a economia, a infraestrutura, as cadeias produtivas, a biodiversidade, a saúde, entre outros aspectos, estão sendo afetados pelas mudanças climáticas. O Brasil tem vantagens estratégicas enormes, como a possibilidade de reduzir fortemente as emissões de gases de efeito estufa, com ganhos importantes para a sociedade. Temos um potencial de geração de energia solar e eólica que nenhum outro país possui. Mas também temos vulnerabilidades, como um agronegócio dependente do clima e a geração de hidroeletricidade dependente da chuva. Temos também 8.500 km de áreas costeiras sensíveis ao aumento do nível do mar, e áreas urbanas vulneráveis a eventos climáticos extremos. Temos que construir uma socioeconomia mais justa e com clima e meio ambiente integrados de modo sustentável.Climate change constitutes one of the greatest challenges facing humanity today. It is urgent to understand how Brazilian ecosystems, the economy, infrastruc ture, produc tion chains, biodiversity, health, among other aspects, are being affected by climate change. Brazil has enormous strategic advantages, such as the possibility of strongly reducing greenhouse gas emissions, with important gains for society. We have a potential for generating solar and wind energy that no other country has. But we also have vulnerabilities, such as climate-dependent agribusiness and raindependent hydroelectricity generation. We also have 8,500 km of coastal areas sensitive to sea level rise, and urban areas vulnerable to extreme weather events. We have to build a fairer socio-economy, with climate and environment integrated in a sustainable way

    Uma nova era geológica em nosso planeta: o Antropoceno?

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    Nosso planeta seguiu uma evolução determinada pelas forças geológicas desde sua origem, há cerca de 4,5 bilhões de anos. Ao longo dessa jornada, passou por transformações significativas em sua crosta e atmosfera. Com o início da Revolução Industrial, na segunda metade do século XVIII, um novo agente de mudança se somou às transformações geológicas. O rápido crescimento populacional – somos 7,3 bilhões de habitantes hoje, e seremos cerca de 10 bilhões em 2050 –, associado ao uso excessivo de recursos naturais, fez com que muitos indicadores de saúde da Terra saíssem da região segura. A partir de 1950, o desenvolvimento humano e suas implicações no ecossistema terrestre crescem exponencialmente. Atualmente, uma grande fração das áreas continentais sem gelo é ocupada por atividades humanas como agricultura e urbanização, entre outras.Our planet has followed an evolutionary path determined by geological forces since its origin about 4.5 billion years ago. Throughout its evolution, the Earth has undergone significant changes in its crust and atmosphere. With the onset of the Industrial Revolution around 1750, a new agent of change has been added to the geological transformations. Rapid population growth (we are 7.3 billion people today, and we will be about 10 billion in 2050) associated with the excessive use of natural resources has brought several of the health indicators of our planet outside safe boundaries. Especially after 1950, human development and its implications on terrestrial ecosystem have grown exponentially. Currently, a large fraction of the continental areas without ice is occupied for human activities such as agriculture, grazing pastures, and urbanization, among others

    Spatiotemporal assessment of particulate matter (PM10 and PM2.5) and ozone in a Caribbean urban coastal city

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    Air pollution has become a critical issue in urban areas, so a broad understanding of its spatiotemporal characteristics is important to develop public policies. This study analyzes the spatiotemporal variation of atmospheric particulate matter (PM10 and PM2.5) and ozone (O3) in Barranquilla, Colombia from March 2018 to June 2019 in three monitoring stations. The average concentrations observed for the Móvil, Policía, and Tres Avemarías stations, respectively, for PM10: 46.4, 51.4, and 39.7 μg/m3; for PM2.5: 16.1, 18.1, and 15.1 μg/m3 and for O3: 35.0, 26.6, and 33.6 μg/m3. The results indicated spatial and temporal variations between the stations and the pollutants evaluated. The highest PM concentrations were observed in the southern part of the city, while for ozone, higher concentrations were observed in the north. These variations are mainly associated with the influence of local sources in the environment of each site evaluated as well as the meteorological conditions and transport patterns of the study area. This study also verified the existence of differences in the concentrations of the studied pollutants between the dry and rainy seasons and the contribution of local sources as biomass burnings from the Isla Salamanca Natural Park and long-range transport of dust particles from the Sahara Desert. This study provides a scientific baseline for understanding air quality in the city, which enables policy makers to adopt efficient measures that jointly prevent and control pollution

    Monitoring of atmospheric aerosol particles on the Antarctic Peninsula

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    Atmospheric aerosol particles have been sampled since 1985 at the Brazilian Antarctic station, Comandante Ferraz (62 degrees 05' S, 58 degrees 23.5' W). Stacked filter units were used to collect particles with an aerodynamic diameter of less than 10 mu m. The elemental concentration Was measured by particle-induced X-ray emission, yielding data for 23 elements: Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Se, Br, Rb, Sr, Zr and Pb. The detection limit was typically near 5 ng m(-3) for elements with atomic number (Z) less than 20, and 0.1 ng m(-3) for 21 < Z < 30. Principal-factor and cluster analyses identified four sources for the Antarctic aerosol: fine and coarse sea salt, soil dust and sulphates. The fine-mode non-sea-salt sulphate concentration showed a clear seasonal pattern accompanying the biological cycle of algae, with minimum during winter. Some elements. such as Ni and Pb, showed very high enriched concentrations relative to the bulk sea-water composition. This indicates the existence of sources of regional or long-range transported pollution

    Spatiotemporal assessment of particulate matter (PM10 and PM2.5) and ozone in a Caribbean urban coastal city

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    Air pollution has become a critical issue in urban areas, so a broad understanding of its spatiotemporal characteristics is important to develop public policies. This study analyzes the spatiotemporal variation of atmospheric particulate matter (PM10 and PM2.5) and ozone (O3) in Barranquilla, Colombia from March 2018 to June 2019 in three monitoring stations. The average concentrations observed for the Móvil, Policía, and Tres Avemarías stations, respectively, for PM10: 46.4, 51.4, and 39.7 µg/m3; for PM2.5: 16.1, 18.1, and 15.1 µg/m3 and for O3: 35.0, 26.6, and 33.6 µg/m3. The results indicated spatial and temporal variations between the stations and the pollutants evaluated. The highest PM concentrations were observed in the southern part of the city, while for ozone, higher concentrations were observed in the north. These variations are mainly associated with the influence of local sources in the environment of each site evaluated as well as the meteorological conditions and transport patterns of the study area. This study also verified the existence of differences in the concentrations of the studied pollutants between the dry and rainy seasons and the contribution of local sources as biomass burnings from the Isla Salamanca Natural Park and long-range transport of dust particles from the Sahara Desert. This study provides a scientific baseline for understanding air quality in the city, which enables policy makers to adopt efficient measures that jointly prevent and control pollution

    Robust relations between CCN and the vertical evolution of cloud drop size distribution in deep convective clouds

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    In-situ measurements in convective clouds (up to the freezing level) over the Amazon basin show that smoke from deforestation fires prevents clouds from precipitating until they acquire a vertical development of at least 4 km, compared to only 1-2 km in clean clouds. The average cloud depth required for the onset of warm rain increased by similar to 350 m for each additional 100 cloud condensation nuclei per cm(3) at a super-saturation of 0.5% (CCN0.5%). In polluted clouds, the diameter of modal liquid water content grows much slower with cloud depth (at least by a factor of similar to 2), due to the large number of droplets that compete for available water and to the suppressed coalescence processes. Contrary to what other studies have suggested, we did not observe this effect to reach saturation at 3000 or more accumulation mode particles per cm(3). The CCN0.5% concentration was found to be a very good predictor for the cloud depth required for the onset of warm precipitation and other microphysical factors, leaving only a secondary role for the updraft velocities in determining the cloud drop size distributions. The effective radius of the cloud droplets (r(e)) was found to be a quite robust parameter for a given environment and cloud depth, showing only a small effect of partial droplet evaporation from the cloud's mixing with its drier environment. This supports one of the basic assumptions of satellite analysis of cloud microphysical processes: the ability to look at different cloud top heights in the same region and regard their r(e) as if they had been measured inside one well developed cloud. The dependence of r(e) on the adiabatic fraction decreased higher in the clouds, especially for cleaner conditions, and disappeared at r(e)>=similar to 10 mu m. We propose that droplet coalescence, which is at its peak when warm rain is formed in the cloud at r(e)=similar to 10 mu m, continues to be significant during the cloud's mixing with the entrained air, cancelling out the decrease in r(e) due to evaporation

    Evolution of the Action Plan for Prevention and Control of Deforestation in the Brazilian Amazon

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    The present study examined the evolution of the implementation of the Action Plan for the Prevention and Control of Deforestation in the Brazilian Amazon (PPCDAm). With this purpose, it was performed the analysis of: scientific publications that characterize deforestation in the Brazilian Amazon; documents comprising the Phase I (2004-2008), Phase II (2009-2011) and Phase III (2012-2015) of the PPCDAm; independent assessments of the Phase I (performed by Abdala, 2008) and the Phase II PPCDAm (performed by Ipea; GIZ; Eclac, 2011); and impacts of the PPCDAm in reducing deforestation. It is concluded that the implementation of the PPCDAm has brought significant results to control the deforestation in the Brazilian Amazon, but improvements aimed at attaining the objectives of the promotion of sustainable activities in the region are still needed.O presente estudo analisou a evolução da implementação do Plano de Ação para Prevenção e Controle do Desmatamento na Amazônia Legal (PPCDAm). Para tal, foi realizada análise de: publicações científicas que caracterizam o problema identificado; documentos que compreendem a Fase I (2004-2008), a Fase II (2009-2011) e a Fase III (2012-2015) do PPCDAm; avaliações realizadas sobre a Fase I (realizada por Abdala, 2008) e sobre a Fase II do PPCDAm (realizada por Ipea; GIZ; Cepal, 2011); e impactos do PPDCAm na redução do desmatamento. Conclui-se que o PPCDAm trouxe resultados significativos para a contenção do desmatamento na Amazônia Legal, mas ainda se fazem necessários aprimoramentos para que sejam alcançados os objetivos de promoção de atividades sustentáveis na região.

    A comparison of dry and wet season aerosol number fluxes over the Amazon rain forest

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    Vertical number fluxes of aerosol particles and vertical fluxes of CO(2) were measured with the eddy covariance method at the top of a 53 m high tower in the Amazon rain forest as part of the LBA (The Large Scale Biosphere Atmosphere Experiment in Amazonia) experiment. The observed aerosol number fluxes included particles with sizes down to 10 nm in diameter. The measurements were carried out during the wet and dry season in 2008. In this study focus is on the dry season aerosol fluxes, with significant influence from biomass burning, and these are compared with aerosol fluxes measured during the wet season. Net particle deposition fluxes dominated in daytime in both seasons and the deposition flux was considerably larger in the dry season due to the much higher dry season particle concentration. The particle transfer velocity increased linearly with increasing friction velocity in both seasons. The difference in transfer velocity between the two seasons was small, indicating that the seasonal change in aerosol number size distribution is not enough for causing any significant change in deposition velocity. In general, particle transfer velocities in this study are low compared to studies over boreal forests. The reasons are probably the high percentage of accumulation mode particles and the low percentage of nucleation mode particles in the Amazon boundary layer, both in the dry and wet season, and low wind speeds in the tropics compared to the midlatitudes. In the dry season, nocturnal particle fluxes behaved very similar to the nocturnal CO(2) fluxes. Throughout the night, the measured particle flux at the top of the tower was close to zero, but early in the morning there was an upward particle flux peak that is not likely a result of entrainment or local pollution. It is possible that these morning upward particle fluxes are associated with emission of primary biogenic particles from the rain forest. Emitted particles may be stored within the canopy during stable conditions at nighttime, similarly to CO(2), and being released from the canopy when conditions become more turbulent in the morning.National Institute for Research in the Amazon (INPA)LBACNPq/MCTFAPES

    Aerosol number fluxes over the Amazon rain forest during the wet season

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    Number fluxes of particles with diameter larger than 10 nm were measured with the eddy covariance method over the Amazon rain forest during the wet season as part of the LBA (The Large Scale Biosphere Atmosphere Experiment in Amazonia) campaign 2008. The primary goal was to investigate whether sources or sinks dominate the aerosol number flux in the tropical rain forest-atmosphere system. During the measurement campaign, from 12 March to 18 May, 60% of the particle fluxes pointed downward, which is a similar fraction to what has been observed over boreal forests. The net deposition flux prevailed even in the absolute cleanest atmospheric conditions during the campaign and therefore cannot be explained only by deposition of anthropogenic particles. The particle transfer velocity v(t) increased with increasing friction velocity and the relation is described by the equation v(t) = 2.4x10(-3)xu(*) where u(*) is the friction velocity. Upward particle fluxes often appeared in the morning hours and seem to a large extent to be an effect of entrainment fluxes into a growing mixed layer rather than primary aerosol emission. In general, the number source of primary aerosol particles within the footprint area of the measurements was small, possibly because the measured particle number fluxes reflect mostly particles less than approximately 200 nm. This is an indication that the contribution of primary biogenic aerosol particles to the aerosol population in the Amazon boundary layer may be low in terms of number concentrations. However, the possibility of horizontal variations in primary aerosol emission over the Amazon rain forest cannot be ruled out.National Institute for Research in the Amazon (INPA)LBA infrastructure teamCNPq/MCT Millennium Institute ProgramFAPES
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