Publicações

The decaying organic matter releases, among other gases, methane (CH4), composed of semi-opaque to infrared radiation has an important role in the greenhouse. The knowledge of how the lentic systems emit gases from the anaerobic decomposition of non lignified material, primarily composed of herbaceous plants and areas of peeling macrophytes has been highlighted in several studies. This paper presents the results of a preliminary test to work on the emission of greenhouse gases in reservoirs on the methane produced in one of the ponds for water supply INPE – National Institute for Space Research, Cachoeira Paulista / SP. To determine the flow of methane was carried out a campaign in December 2010 and the gas flow determined using the static chamber technique. The environmental parameters measured were the temperature of air and water, pH, redox potential, conductivity, dissolved oxygen and total dissolved solids. The overall average of valid flows was 59.1 ± 91.98 mgCH4/m2/dia and analysis of the environmental parameters indicates that the methane concentration was high in environments with a pH lower than 4 and lower levels of dissolved oxygen in water.

A rede hidrográfica brasileira tem grande potencial para a geração de energia por meio da implantação de usinas hidrelétricas. O entendimento de como ocorrem os processos de emissão de gases de efeito estufa em reservatórios de centrais hidrelétricas vem sendo amplamente questionado por diversos setores. Neste trabalho foi realizado um estudo preliminar para validar medidas a serem implementadas na pesquisa de emissão em represas. Assim, estimou-se a emissão natural de metano para a atmosfera na Lagoa Rodrigo de Freitas, no Rio de Janeiro, onde foram realizadas duas campanhas em 2011. Determinou-se o fluxo de metano utilizando a técnica da câmara estática para a coleta do ar e a análise das amostras efetuada por cromatografia gasosa. A média geral dos fluxos foi de 47,2 + – 24,4 mgCH4m-2d-1 de emissão de gás para a atmosfera. Foram medidos parâmetros ambientais e observada a influência destas variáveis no processo de emissão do metano.

A decomposição de matéria orgânica libera o metano (CH4), composto com destacado papel na regulação da temperatura do planeta. Este trabalho apresenta resultados preliminares da emissão deste gás na região aonde será instalada a usina hidrelétrica de Santo Antônio, em Rondônia, projeto fomentado pela Agência Nacional de Energia Elétrica ANEEL. Duas campanhas foram realizadas como ensaio preliminar do método empregado no projeto: uma em lagoa natural, utilizada para o abastecimento do INPE de Cachoeira Paulista, e outra na Lagoa Rodrigo de Freitas, no Rio de Janeiro, que é uma lagoa costeira que sofre interferências antrópicas. Em todos os lugares foram efetuadas coletas em diferentes pontos das lagoas, na jusante e montante do rio Madeira/RO. As amostras foram analisadas em laboratório por meio de análise cromatográfica. Nas lagoas as medidas de emissão de metano para a atmosfera apresentaram fluxos médios próximo de 50 mgCH4m-2d-1, indicando que elas são emissora deste gás com valores próximos entre elas mesmo com suas diferentes características. Já no rio Madeira, os valores dos fluxos obtidos a montante foram altos e tem valores maiores que a jusante. Uma das justificativas é a grande quantidade de sedimentos e uma quantidade pouco comum de material flutuante: galhos de árvores, folhas e mesmo grandes troncos. A deposição contínua de sedimentos carreados pelo rio, misturados a restos vegetais, constituiu uma ótima fonte para a produção de metano. E a turbulência da água também tem um papel importante na emissão de metano dos corpos d’água. Algumas variáveis que podem afetar as emissões de metano, como a pH, temperatura, oxigênio dissolvido foram medidas.

Density maps are one of the most common and powerful use of lightning data, and its application became as more efficient as more detailed the maps are. When leading with data from Lightning Location Systems (LLSs), which means a stochastic phenomenon that depends on several detection conditions, some aspects must be included in the analysis to overcome the system performance and other random errors. Some of these limitations are minimized by considering the detection efficiency and location accuracy in the analysis. For the Brazilian Lightning Detection Network (BrasilDAT), the detection efficiency is normally evaluated through models and the location accuracy through confidence ellipses. In this work we have produced lightning density maps along the ITAIPU power transmission lines using the most recent detection efficiency model of the network developed in Brazil (MED4), as well as the Gaussian confidence ellipses as a smoothing method associated to the location accuracy of each discharge. The model increased the density in about 50% over the entire region. The spatial pattern did not present considerable changes. The Gaussian smooth seems to work well according to our purpose. The use of these two improvements might bring up more detailed maps and better results.

Lightning distribution maps as a climatological approach are often associated to physical effects (geographical and meteorological aspects). Despite of some concerns regarding the lightning location systems (LLS) performance for some specific regions, the physical effects are fairly clear and the results quite reliable. However, in some cases, the lightning activity in a specific region might be associated to different physical effects. In this work we intend to show that on this background, a distinct perception scale might occur depending on the map resolution. Ten years of data (Jan 1999 to Dec 2009) from the Brazilian Lightning Detection Network (BrasilDAT) were used to create the lightning distribution using density maps. Maps with different spatial resolution were created over two regions: Belo Horizonte and Sao Paulo. High resolution maps were produced using an adapted smooth kernel analysis based on the location accuracy of the LLS. This technique seems, like other previous proposed methods, to overcome some issues regarding the amount of lightning data inside each grid cell on the density map. By this analysis, we shall show that the perception of the physical effects associated to the lightning distribution might be different depending on the spatial resolution used on the maps.

We live in a changing world and this acceleration of change provides a strong motivation for research in GeoInformatics. Our tools and methods for representing and handling land cover data should be capable of dealing with change. In this work we developed a land cover model to handle the evolution of land cover objects. This consists of an abstract data type (land cover object) and uses a limited number of spatial operations such as create and split to elicit the changes it suffers in time. We present an application of the model to the data provided by the Brazilian Amazon Deforestation Monitoring Program.

Currently Amazon land use/cover changes are closely related to its impact on regional policies. These policies can be based on deforestation data resulting from land cover models, which may be based on on empirical analysis of potential factors determining its patterns and processes. However, when only data from total deforestation are shown, it can cause misinterpretation of the recently cleared areas, inducing poor decisionmaking. In the present study were constructed deforestation risk maps of Brazilian Amazon from the simulations results obtained by a regional scale model for the Brazilian Amazon called LuccME / BRAmazonia. This model was built using a modeling framework developed by CCST / INPE, which allows to build integrated models that combine different modules of demand, transition potential and land use/cover changes allocation. We made simulations with two different demand scenarios (Baseline and carbon Emission Reduction Target scenario) for 2020, and the second one was chosen to create the risk map. This map represents the difference between foreseen deforestation in 2020 and actual deforestation in 2006. Thus, it was possible to find most susceptible areas to deforestation in coming years.

Este artigo faz um estudo das soluções de acoplamento entre diferentes escalas no TerraME, levanta novos requisitos e propõe uma estrutura única na tentativa de atender a todas as implementações existentes. O principal objetivo é discutir como integrar os esforços desenvolvidos pelos diferentes trabalhos, alcançando melhorias que irão auxiliar o exercício da modelagem.

O presente estudo avaliou as mudanças na precipitação e temperatura projetadas pelo modelo ETA_HadCM3 para o futuro (2011-2099), na RMRJ. A validação do clima presente (1961-1990), gerado pelo modelo, mostrou um erro médio sistemático de -0,5mm/dia para a precipitação e 1,6°C para a temperatura. O ETA_HadCM3 projeta, ao longo do período de 2011-2099, um aumento no valor máximo da Tmax que pode chegar a até 43°C nos municípios de Japeri e Nova Iguaçu. Os máximos acumulados diários de chuva serão mais intensos nas cidades do Rio de Janeiro, Niterói e Maricá, podendo alcançar 72mm/dia ao sul de Niterói de 2071-2099.

The advent of high-speed motion CCD video cameras allowed the use of temporal highresolution video images of lightning flashes. High-speed cameras are now an essential tool in lightning research. Being able to see and analyze sequential, time resolved images of lightning processes is greatly improving our understanding of this complex phenomenon. Flash characteristics like stroke multiplicity, interstroke time interval, flash duration, number of ground contacts are easily determined. With these cameras, the missing of strokes that occur at relatively short time intervals is practically excluded. The presence of continuing current events, the waveshape of their intensity and the occurrence of M components can be observed. Also, the elapsed time since the return stroke and time interval between successive M components can be measured. In addition, recoil leaders that retrace fine branch structures during the propagation of positive leaders to ground were observed for the first time with these cameras. This review paper will describe some recent findings obtained with high-speed videos.