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Brazil has nearly 5 million hectares of forest planted with species of the genus Eucalyptus and Pinnus and nearly 70% of these forests are for the manufacture of cellulose pulp. Eucalyptus planted forests are being implemented in different regions of the country, developing at sites with different topographies and rainfall patterns. But then some factors limit the geographic distribution of plantations. Remote sensing has surged ahead in the forest sector, and with the use of techniques of image interpretation, we can identify and map the Eucalyptus and differentiate them from other vegetation types, and quantify them. The aim of this study was to map the Eucalyptus spp. using satellite images and to evaluate the geographic distribution, including soil types and slope of the land where these plantations are being developed. Images from the Landsat / TM for the year 2008 and the plantings were mapped by visual interpretation of images. The areas of plantations were compared with those found in the work areas of Kronka et al. (2002), which showed an increase of 75,123 ha in the entire state. The species of this genus have some limitations of climate, soil and topography. Understanding these factors and the choice of sites that meet the minimum requirements of Eucalyptus facilitates their growth, thus ensuring its productivity.

The aim of this investigation is to analyze the phenomenology of positive and negative (stepped-, dart- and recoil) leaders observed in natural lightning from simultaneous high-speed video recordings and electric field measurements. For that intent we have used two different high-speed cameras (obtained by two different cameras, Red Lake Motion Scope 8000S and Photron Fastcam 512 PCI, operating at frame rates ranging from 1000 or 8000 frames per second) and two different types of electric field sensors (slow and fast) in addition to data from a lightning locating system (BrasilDat). All the instruments were GPS time synchronized in order to avoid ambiguities in the analysis and allow us to estimate the peak current of and the distance to each flash that was detected by BrasilDat. From these data it is possible to calculate the two-dimensional speed of each observed leader, allowing us to obtain its statistical distribution along with its correlation to other characteristics of the associated flash, such as return stroke peak current, interstroke interval and presence and duration of continuing current after the return stroke initiated by the leader. Also, the availability of electric field data makes it possible to correlate it to the optical characteristics of each leader type, providing us new insights on the microphysics of these phenomena. In the analyzed dataset, the speeds of positive leaders and negative dart-leaders follow a lognormal distribution at the 0.05 level (according to the Shapiro-Wilk test), while the negative steppedleaders have a similar distribution even though according to a relatively weaker test (KolmogorovSmirnov). Unfortunately, due to the range of frame rates reached by the used cameras, only the minimum propagation speeds could be estimated in the recoil leaders that were observed.

Schonland et al. (1938), in their seminal streak camera studies of lightning, have identified a peculiar type of negative stepped leader that they termed β, a rather rare variant of the type β leader and in it the second and slower stage of the leader is associated with the appearance of one or more fast dart streamers, which travel rapidly down from the cloud along the previously formed track and cease when they have caught up with the slower leader-tip. They reported four events, two were accompanied by a dart streamer (a nomenclature we will keep for historical reasons), one event contained two examples, and one event that was not described in detail. During a July-August 2007 campaign in Tucson, Arizona, USA, we recorded four downward leaders that fit in the type-β22 description given by Schonland et al. (1938). All cases occurred between about 12 and 32 km from a high-speed camera that was operating at 4000 frames per second. Two cases were produced by the first stroke in a flash, and one case was associated with a subsequent stroke that produced a new ground termination. Our fourth case was a subsequent stroke that began with a dart leader and then changed to a type- stepped leader approximately 1350 m above the ground; in this case, we observed a dart streamer (with the leader tip at about 720 m from the ground) about 3.25 ms after the stepped progression began and the return stroke occurred 2 ms later. All the dart streamers that we observed had speeds between 10 6 and 10 7 m s -1 -2 , in agreement with previous observations of recoil leaders (Saba et al., 2008); therefore, we suggest that the type- negative leaders are the visible manifestation of the development of recoil leaders that were initiated inside the cloud and propagate below the cloud-base, during the development of a bipolar, bidirectional leader that precedes a lightning flash to ground. The recoil leaders develop in previously ionized channels that are produced by the in-cloud 2 positive portion of a bidirectional leader, and when they reach the tip of the negative downward portion, they produce an intense pulse of luminosity that optically appears as a dart streamer.

Lightning data obtained by the Brazilian Lightning Detection Network (BrasilDat) in the southeastern region of Brazil (latitudes from 22S to 24S and longitudes from 43W to 47.4W) from 1999 to 2009 were studied in terms of spatial and temporal variations of the flash counts. The spatial variation shows clear effects of the altitude and urban activity on the flash counts. These aspects modulated the flash counts in a way to produce two large lightning spots, one located over the city of São Paulo and the other with almost a same area located near the city of Volta Redonda in the south part of the state of Rio de Janeiro. While the first is related to the heat island produced by the urban activity, the other is related to a particular feature of the relief characterized by the approximation of the two mountain ridges. For both cities (São Paulo and Volta Redonda) three different comparisons were done involving the flash density (in terms of hours of flashes) for a grid cell of 2x2km, the daily (local time) flash variation, the annual percentage of minutes with more than three (typical value for isolated thunderstorms) flashes with respect to the total number of minutes with flashes and the annual variation of the number of hours of flashes. The results are discussed in the context of the two different physical mechanisms responsible for most convection in the two cities.

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.