Publicações

Regional climate change projections for the last half of the twenty-first century have been produced for South America, as part of the CREAS (Cenarios REgionalizados de Clima Futuro da America do Sul) regional project. Three regional climate models RCMs (Eta CCS, RegCM3 and HadRM3P) were nested within the HadAM3P global model. The simulations cover a 30-year period representing present climate (1961-1990) and projections for the IPCC A2 high emission scenario for 2071-2100. The focus was on the changes in the mean circulation and surface variables, in particular, surface air temperature and precipitation. There is a consistent pattern of changes in circulation, rainfall and temperatures as depicted by the three models. The HadRM3P shows intensification and a more southward position of the subtropical Pacific high, while a pattern of intensification/weakening during summer/winter is projected by the Eta CCS/RegCM3. There is a tendency for a weakening of the subtropical westerly jet from the Eta CCS and HadRM3P, consistent with other studies. There are indications that regions such of Northeast Brazil and central-eastern and southern Amazonia may experience rainfall deficiency in the future, while the Northwest coast of Peru-Ecuador and northern Argentina may experience rainfall excesses in a warmer future, and these changes may vary with the seasons. The three models show warming in the A2 scenario stronger in the tropical region, especially in the 5A degrees N-15A degrees S band, both in summer and especially in winter, reaching up to 6-8A degrees C warmer than in the present. In southern South America, the warming in summer varies between 2 and 4A degrees C and in winter between 3 and 5A degrees C in the same region from the 3 models. These changes are consistent with changes in low level circulation from the models, and they are comparable with changes in rainfall and temperature extremes reported elsewhere. In summary, some aspects of projected future climate change are quite robust across this set of model runs for some regions, as the Northwest coast of Peru-Ecuador, northern Argentina, Eastern Amazonia and Northeast Brazil, whereas for other regions they are less robust as in Pantanal region of West Central and southeastern Brazil.

During the austral summer and winter 2009, the Amazon basin, drained by the Amazon River and its tributaries, was hit by heavy flooding. This year the water level rose higher and stayed longer than it has in several decades. According to national and international press, almost 376 000 people were left homeless and 40 died because of the floods. The communities living on the river banks and on the urban areas of cities like Manaus suffered the impacts of the rising waters, and the floods affected the exotic wildlife and the endangered species. Damages were estimated on the order of $200 million U.S. in the Brazilian state of Amazonas.

The current work describes the use of multidimensional Euclidean geometric distance (EGD) and Bayesian methods to characterize and classify the sky and cloud patterns present in image pixels. From specific images and using visualization tools, it was noticed that sky and cloud patterns occupy a typical locus on the red-green-blue (RGB) color space. These two patterns were linearly distributed parallel to the RGB cube’s main diagonal at distinct distances. A characterization of the cloud and sky patterns EGD was done by supervision to eliminate errors due to outlier patterns in the analysis. The exploratory data analysis of EGD for sky and cloud patterns showed a Gaussian distribution, allowing generalizations based on the central limit theorem. An intensity scale of brightness is proposed from the Euclidean geometric projection (EGP) on the RGB cube’s main diagonal. An EGD-based classification method was adapted to be properly compared with existing ones found in related literature, because they restrict the examined color-space domain. Elimination of this limitation was considered a sufficient criterion for a classification system that has resource restrictions. The EGD-adapted results showed a correlation of 97.9% for clouds and 98.4% for sky when compared to established classification methods. It was also observed that EGD was able to classify cloud and sky patterns invariant to their brightness attributes and with reduced variability because of the sun zenith angle changes. In addition, it was observed that Mie scattering could be noticed and eliminated (together with the reflector’s dust) as an outlier during the analysis. Although Mie scattering could be classified with additional analysis, this is left as a suggestion for future work.

The socio-economic impacts of environmental stresses associated with global environmental change depend to a large extent on how societies organize themselves. Research on climate-related societal impacts, vulnerability and adaptation is currently underdeveloped, prompting international global environmental change research institutions to hold a series of meetings in 20092010. One of these aimed at identifying needs in middle-income and low-income countries (MLICs), and found that effective responses to the challenge of reducing vulnerability and enhancing adaptation will drive research and policy into challenging and innovative areas of research. Producing impacts, vulnerability and adaptation knowledge requires greater inclusion of MLIC researchers and a rethinking of the research structures, institutions and paradigms that have dominated global change research to date. Scientific literature discussed in this article suggests that governance issues need to become central objects of empirically based, detailed, multiscalar and action-oriented research, and that this needs to address the politically sensitive and seemingly intractable issue of reducing global inequities in power and resource distribution. The scientific literature suggests that without effective action in those directions, current trends toward greater inequality will continue to both reflect and intensify global environmental threats and their impacts.

Contemporary societies are being transformed by growing preoccupation with global environmental risks. The scientific basis for worries about human-induced climate change has consolidated, but many dimensions and implications remain uncertain and imprecise. In this area of what has been called post-normal science, facts are uncertain, values in dispute, stakes high, and decisions urgent. Plurality is its essence, and meaning-making fills gaps left by uncertainties. Actors – scientists, decision-makers, industry representatives, and members of environmental groups and the general public – variously clash and converge in their attempts to shape how societies understand the threat and what should be done about it. Among those favoring preventive action, some downplay or deny the uncertainties. Others – often with important leadership and financing by vested interests – exaggerate the uncertainties, or define them and the sociopolitical and economic implications of action to reduce carbon emissions in ways that undermine policy. Although everyone involved tends to focus on scientific arguments, choices of explanation by all the involved actors, and their very engagement in the debate, reveal political arrangements, moral commitments, and sociocultural ties as much as individual or group interests.

We used a climate-vegetation-natural fire (CVNF) conceptual model to evaluate the sensitivity and vulnerability of forest, savanna, and the forest-savanna transition to environmental changes in tropical South America. Initially, under current environmental conditions, CVNF model results suggested that, in the absence of fires, tropical forests would extend c. 200 km into the presently observed savanna domain. Environmental changes were then imposed upon the model in temperature, precipitation and lightning strikes. These changes ranged from 2 to 6 degrees C warming, +10 to -20% precipitation change and 0 to 15% increase in lightning frequency, which, in aggregate form, represent expected future climatic changes in response to global warming and deforestation. The most critical vegetation changes are projected to take place over the easternmost portions of the basin, with a widening of the forest-savanna transition. The transition width would increase from 150 to c. 300 km, with tree cover losses ranging from 20 to 85%. This means that c. 6% of the areas currently covered by forests could potentially turn into grass-dominated savanna landscapes. The mechanism driving tree cover reduction consists of the combination of less favorable climate conditions for trees and more fire activity. In addition, this sensitivity analysis predicts that the current dry shrubland vegetation of northeast Brazil could potentially turn into a bare soil landscape.

Irrigation with treated domestic sewage wastewater (TSE) is an agricultural practice to reduce water requirements of agroecossystems and the nutrient load impact on freshwaters, but adverse effects on soil chemical (salinization, sodification, etc.) and soil physical properties (alteration in soil porosity and hydraulic conductivity, etc.) have been reported. This study aimed to define some relationships among these changes in an Oxisol using multivariate analysis. Corn (Zea mays L.) and sunflower (Helianthus annuus L.) were grown for two years, irrigated with TSE. The following soil properties were determined: Ca2+; Mg2+; Na+; K+ and H + Al contents, cationic exchangeable capacity (CEC), sum of bases (SB), base saturation (V), texture (sand, silt and clay), macro-, micro-, and cryptoporosity (VMA, VMI and VCRI), water content at soil saturation (θS) and at field capacity (θFC), residual water content (θR), soil bulk density (ds), water dispersed clay (WDC) and saturated hydraulic conductivity (KSAT). Factor analysis revealed the following six principal factors: Fine Porosity (composed of Na+; K+; WDC, θR, θRFC, and VCRI); Large Porosity (θS, ds, VMA, Vs); Soil CEC (Ca2+; Mg2+; CEC, SB, V); Soil Acidity (H + Al); and Soil Texture (factors 5 and 6). A dual pore structure appears clearly to the factors 1 and 2, with an apparent relationship between fine porosity and the monovalent cations Na+ and K+. The irrigation (with potable sodic tap water or sewage wastewater) only had a significant effect on Fine Porosity and Large Porosity factors, while factors 3 and 4 (Soil CEC and Soil Acidity) were correlated with soil depth. The main conclusion was a shift in pore distribution (large to fine pores) during irrigation with TSE, which induces an increase of water storage and reduces the capacity of drainage of salts.

The Intergovernmental Panel on Climate Change (IPCC) projections for this century would certainly result in a suite of biophysical and socio-economic impacts on the Brazilian coastal zone that would ultimately affect several sectors, including natural ecosystems, fisheries, transportation, tourism and recreation, infrastructure and local communities.

Composições de 16 dias de índices de vegetação do sensor Moderate Resolution Imaging Spectroradiometer (MODIS), com resolução espacial de 250 metros, a bordo do satélite TERRA, foram utilizadas para caracterizar a dinâmica sazonal, no período de 2008, de duas fitofisionomias do bioma Mata Atlântica e analisar a sua dinâmica espectral. Os índices Normalized Difference Vegetation Index (NDVI) e Enhanced Vegetation Index (EVI), calculados a partir dos dados do sensor MODIS, e uma base comum de pixels, foram comparados entre si e com uma base de dados de ordem climática (temperatura e precipitação), para cada fitofisionomia. Os resultados indicaram que os fragmentos de floresta estacional decídua e floresta ombrófila mista apresentam um padrão sazonal comum, porém, com variações de amplitude em relação a cada índice. O EVI apresentou-se mais sensível às variações anuais da vegetação em relação ao NDVI, mostrando-se mais eficiente. Para ambas as formações florestais, se estabelece uma relação positiva entre o perfil EVI e NDVI com as variações de temperatura. A dinâmica espectral/temporal revelou um contraste marcante sob condições sazonais distintas, convergindo com o padrão apresentado pelos índices de vegetação. Os dados produzidos indicam potencialidades da utilização do sensor MODIS para o monitoramento contínuo das formações florestais de Mata Atlântica, com resolução espacial moderada e alta resolução temporal.

A modelagem numérica é uma importante ferramenta para a estimativa e previsão dos recursos de energia solar, imprescindíveis para o desenvolvimento, implementação e operação de projetos para aproveitamento dessa fonte energética limpa e de caráter renovável. O artigo apresenta o estudo realizado para desenvolvimento e adaptação de modelos empíricos para estimativa de irradiação solar em superfície em dois âmbitos: com abrangência local para localidades específicas e com abrangência regional para todo o território brasileiro. Os baixos desvios estatísticos entre as estimativas dos modelos e as medidas coletadas em superfície (RMSE de 17% a 23% para o modelo regional e de 15% a 26% para os modelos locais) mostraram a boa confiabilidade das estimativas fornecidas pelos mesmos. Adicionalmente, o desempenho de dois modelos clássicos da literatura (Ruth e Chant, 1976; Collares-Pereira e Rabl, 1979)foram comparados com o modelo local para São Martinho da Serra RS, verificando-se boa concordância entre suas estimativas, com exceção dos períodos de céu limpo (Kt > 0,7), nos quais o modelo local mostrou-se superior aos modelos clássicos.

A disponibilidade de dados hiperespectrais trouxe expectativas nos meios acadêmicos e empresariais quanto à potencialidade de sua aplicação no setor florestal. O objetivo deste trabalho foi avaliar a aplicação de dados hiperespectrais do sensor Hyperion EO-1 na caracterização espectral de plantios de Eucalyptus spp. e os efeitos da geometria de iluminação nesse processo. Para avaliar a geometria de iluminação foram utilizados dados topográficos provenientes do SRTM (Shuttle Radar Topography Mission) e as condições de iluminação presentes no momento da aquisição da imagem de satélite, gerando assim um fator de iluminação para a área de estudo. Os dados hiperespectrais foram convertidos para valores de FR de superfície, os quais passaram a constituir os dados fundamentais de todo o trabalho. A área de estudo contemplou os plantios do gênero Eucalyptus spp., pertencentes à empresa Fibria S.A., localizados no município de Capão Bonito (SP). Foram coletados dados de diferentes espécies e em diferentes etapas de desenvolvimento, o que caracteriza diferenças estruturais nos dosséis dos plantios. As componentes principais foram aplicadas nos dados e foram confeccionados gráficos dos fatores referentes às duas primeiras componentes, dos quais foram extraídas informações estruturais sobre os plantios.

Pyritic coal wastes produced by a coal beneficiation plant in the state of Santa Catarina in Southern Brazil are acid generating. Here we report the second part of a study evaluating the use of a dry cover to minimize acid mine drainage generation and its release into the environment. This part encompasses the construction and initial monitoring of an experimental pilot-scale unit. Local clays and ash from a power station were used as cover materials. Monitoring started in October 2007 and will extend for at least 4 years. Initial results of the dry cover system constructed using compacted locally available clay and ash look promising. The pH of the drainage ranged from 6.0 to 7.0, within the legal limits for discharge into the environment.