National Institute for Space Research
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Fire emissions in tropical forests: refining the SPITFIRE model using remote sensing data
No full textTropical fires are the most poorly represented fire type in Dynamic Global Vegetation Models (DGVMs), due to an incomplete understanding of the factors driving them. As the time period increases for which remote sensing fire data is available, it becomes possible to assess long-term trends and distinguish between natural interannual variability and the effects of changes in anthropogenic drivers of fire. The SPITFIRE model captures the broad features of global fire regimes, but includes several processes that rely heavily on the accuracy of the input data, products of earlier calculations, and prescribed parameters. In this paper, we develop two alternative approaches for calculating fire danger and burnt areas, whose substitution into SPITFIRE would increase computational efficiency and reduce the required number of weakly constrained input variables and datasets. We first model fire danger as a function of water stress and fuel availability proxies. Second, we test a new burnt area model using a Pareto distribution, which relies on fire counts, thus eliminating the need for rate of fire spread information. Parameters for the fire danger model have yet to be estimated, but the structure is plausible. The burnt area model performs well for Amazonia for a range of grid resolutions and parameter estimates; coarse resolutions produce the most accurate results. More data is required to calibrate the equations across the tropics. These changes could potentially improve predictions of which areas are at risk of burning, but not the extent of damage to standing biomass: this will require further model improvements.Pages: 7337-734
Avaliação do desempenho dos classificadores Isoseg e Bhattacharya para o mapeamento de áreas de cana-de-açúcar no município de Barretos-SP
No full textSugarcane is one of the most important crops for Brazils economy. The increase in global demand for sugarcanes ethanol requires the conversion of areas of conventional crops in sugarcane cultivation areas, making it necessary to know the level of expansion of this culture. The CANASAT project is mapping sugarcane areas in South central Brazil, using visual interpretation to generate sugarcane cultivation maps. The use of automatic classifiers must be improved, searching for new alternatives for mapping sugarcane. This study aimed to apply automatic classifiers for mapping areas of sugarcane in the city of Barretos-SP, comparing the performance of these classifiers with the map of CANASAT project for this municipality. We tested the classifiers Isoseg and Bhattacharya, and the GIS used was SPRING 4.3.3. Comparing the two classifiers evaluated, Bhattacharya achieved the best results, with a Kappa index of 0.47, which is considered good, while the Isoseg was considered reasonable. The sugarcane areas that were at maximum vigor were classified correctly, but in areas at the beginning of vegetative cycle, after harvest or in reform generated errors of omission and inclusion, what shows the need of multitemporal analysis for mapping sugarcane. However, the classification based on visual interpretation still shows up the most appropriate way to do this mapping.Pages: 89-9
Avaliação da evapotranspiração em áreas de cana-de-açúcar no município de Barretos - SP utilizando o produto MOD16A2
No full textThe production of ethanol from sugarcane is very important in the economy of Brazil, showing a significant growth, especially in the Central-South region, in the last years. However, the impacts of sugarcane producing areas should be clarified, through informations that can contribute strategically to actions and policies that maximize the benefits of ethanol and minimize its negative effects. The modification of land-use and land-cover lead to changes in biosphere-atmosphere interaction, since pastures and agricultural areas are converted into sugarcane. Among the variables affected, the evapotranspiration (ET) is one of the most important in the hydrological cycle, making the connection between energy, climate and water availability. In this context, the objective of this study is to evaluate the influence of land-use changes in evapotranspiration in sugarcane areas in the city of Barretos-SP. We used data from MOD16A2 product (evapotranspiration, mm/day), between the 2003 and 2011 years. The variation of evapotranspiration during this period was determined by map algebra. Time series of evapotranspiration was acquired and related with temporal response of rainfall rates in sugarcane areas. In areas of sugarcane expansion was observed an average decrease of 0.22 mm/day in evapotranspiration. In areas where the culture was already inserted and where it was interrupted changing ET was -0.45 mm/day and -0.37 mm/day, respectively. Initial results showed that evapotranspiration presents a significant sensitivity to rainfall.Pages: 105-11
Análise quali-quantitativa do processo de mudança de paisagem em áreas de pântano na região norte de Minas Gerais a partir de imagens de satélite
No full textEnvironmental studies to characterize the process of environmental degradation of different ecosystems are extremely complex. In recent years, satellite images have become a great ally in these types of study, since they have the advantage of allowing the joint analysis of different variables, especially when associated with the temporal series. In this perspective, the study aimed to analyze the process of environmental degradation in areas of marshes, located in the sub-basin of the rio Urucuia, situated in the north of the state of Minas Gerais, from LANDSAT-5/TM images. Characterized by a transition region between the biomes savana and caatinga, areas of marshes suffer strong anthropogenic pressures that are promoting major disturbances and disfiguration of the entire ecosystem. For the analysis were studied images of months more dry for the years 1984 and 2010.The areas of meadows have been identified and mapped and then there was a automatic segmentation, metrics for landscape analysis and the IVDN (vegetation index difference of standard). The results showed that during the period analyzed, these areas fell by around 7.98 times, mainly due to silting. There is a remarkable extinction of fragments of meadow in the landscape both in relation to the area in terms of density, in this period of 26 years. The NDVI showed a change on the surface of the water for values corresponding to areas of exposed soil in the advanced stage of deterioration. With the work it is evident that activities are required for rehabilitation and conservation of these areas.Pages: 7179-718
Caracterização do estado de conservação das formações florestais das reservas legais da bacia do Córrego Penido (Juiz de Fora, MG)
No full textWith the help of Geographic Information Systems (GIS) and Remote Sensing, the present work aims spatialize and analyze the appearance of the vegetation in forest fragments that constitute the legal reserves of Stream Penido, municipality of Juiz de Fora. For this, we used a clipping of satellite image obtained by the TM / LANDSAT 5, august 2011, scene code orbit / point 217/75, with a spatial resolution of 30 meters, the analysis of vegetation cover was made from the combination of bands 2, 4 and 7. The combination of the bands mentioned allowed the separation of those vegetated areas devoid of trees, helping to identify roads and urban areas, water bodies and rocky outcrops, and involve the identification of vegetation structure and forms of relief. The legal reserves are located in private farms, in the basin of the stream Penido and inserted in a disturbed matrix, composed of areas cleared for farming agriculture. His predominant vegetation consists of seasonal forest in the middle stage of regeneration. Near the legal reserve are detected the presence of eucalyptus and a considerable area of pasture dirty with the constant presence of grasses Brachiaria sp. The proposed methodology and fieldwork allowed to assess and diagnose the environmental situation of legal reserves and intervention in the same forest.Pages: 2882-288
Uso da Imagem TM/Landsat-5 para definição da Zona Ripária do Canal Principal do Baixo Rio Doce - Espírito Santo, Brasil
No full textThis study aims to analyze and spatialize flooded area of the lower Rio Doce Espírito Santo, Brazil under the riparian zone perspective. For that enlisted the help of GIS tool with integrated products and remote sensing techniques. Bibliographical searches were conducted, the series of historical precipitation and acquired images (orbital and suborbital) of the Lower Rio Doce, especially those representing peak flows (floods). The use of the image was an important factor in defining the riparian zone, considered one of the most talked variables by the authors dealing with the issue. Thus, given the existence of a (raster) that depicts the reality of the study area in a period of high flow is information that can not be ignored but valuable to planners.Pages: 7071-707
Análise da Formação de Ilhas de Calor em Fortaleza-CE por meio de imagens de satélite
No full textThe urbanization at metropolitan areas has caused changes in various environmental features, such as changes in soil and surface temperature, becoming the starting point for training the phenomenon of Heat Islands. The Heat Islands refers to urban air and surface temperatures that are higher than nearby rural areas.The objective of this papper is to analyze the formation of heat islands in the city of Fortaleza, capital of Ceará. For this study was used three images with temporal variations of three years, collected during the dry northeast region, through the Thematic Mapper sensor on board the Landsat 5 satellite. Using the thermal band which is related to the infrared channel, the figures were transformed digital temperature data surface by means of the algorithm Algorithm Surface Energy Balance for Land (SEBAL).The results have different maximum temperature in each of the images in the three years checked with variations arriving between 7 ° C and 10 ° C in a total of six years in localized areas with higher environmental degradation, which were areas near the center, international airport Fortaleza and neighborhood Mayor Joseph Walter, compared to areas of greater vegetation cover has the characteristics necessary for the formation of heat islands.Pages: 905-91
Identificação das fases de cultivo da cana-de-açúcar a partir do perfil temporal de NDVI do sensor Modis para o estado de São Paulo
No full textThe monitoring of agricultural areas from remote sensing and geotecnology, can contribute significantly, allowing for effective methodologies for low cost. Sao Paulo state is the largest producer of ethanol and sugarcane in Brazil. Thus, it is extremely important to identify areas of sugarcane cultivation and its phases so temporal and spatial. The Modis sensor has characteristics that can be applied for this purpose, mainly due temporal resolution and the MOD13Q1 products. The NDVI images were use, for identification and monitoring of sugarcane. VI Quality and Reliability images were used for the elimination of contaminated pixels in NDVI images. These pixels were replacement considering their nearest neighborhood on temporal profile. The series has been smoothed by average and transformed in slope and variance profile. From the slope profile, a mask was generated whose profile cross the x-axis twice. The final images from the slope and variance, variance images were generated for each profile and were attached, cut from the mask previously generated and classified in an unsupervised manner, highlighting areas where the temporal profile resembles the cultivation of sugarcane. The slope profile allowed identify the phases of peak growth cycle (maximum maturity), harvest, end of harvest and development of sugarcane. The results showed that the methodology was able to identify characteristic profile of sugarcane and their respective stages of cultivation, allowing a strategic view of spatial and temporal dynamics of the whole process of sugarcane cultivation.Pages: 601-60
Diagnóstico ambiental dos conflitos de uso e ocupação do solo nas Áreas de Preservação Permanente da microbacia do Ribeirão Anhumas, município de Itajubá (MG)
No full textThe data generation that helps a municipality planning correctly the land use and occupation, as well as provides studies and information for environmental management, has been facilitated by knowledge and applications of remote sensing techniques and advancement of geotechnologies. In order to guide urban growth and preserve the nature and its resources, the development of environmental diagnosis is fundamental. In this context, the objective of the article was to conduct a study presenting the physical characteristics of the watershed of Anhumas Stream, located in the municipality of Itajubá (MG), which is majority a rural area but has been under pressure due to urban growth and facing the appearance of gated communities, producing an environmental diagnosis and analyzing human alterations that are in agreement or not with the Brazilians Forest Code. Map digital data were used, applying supervised classification method in ALOS satellite images and data analysis using the programming language LEGAL through the software SPRING. The work details the conflict areas of land use and integrated analysis of the normative state of Permanent Preservation Areas (PPA) as a function of slope, rivers and streams, according to the stipulations of the Forest Code. The result showed that the Watershed of Anhumas Stream presents 60.14% (4.15 km²) of PPA discordant with the Forestry Code, whereas 39.56% (2.73 km²) are preserved.Pages: 4526-453
Integração do método do curva número em um banco de dados espacial para a estimativa da precipitação efetiva em bacias hidrográficas
No full textThis paper presents the development - modeling, analysis and implementation of a computational tool that aims at providing the estimation of runoff in a watershed. Thus, the curve number method of the Natural Resource Conservation Service (NRCS) also known as SCS-CN method has been integrated into a spatial database in the form of queries in SQL and Spatial SQL. The tool was built based on the analysis of the requirements, through conceptual modeling, logical design, physical design, development, consultation and implementation. The Database Management System (DBMS) chosen was the PostrgreSQL, with its spatial extension PostGIS. The gvSIG was used as the database viewer. The study area was the Atuba watershed in the metropolitan region of Curitiba-PR. Preliminary results indicate an adequate modeling, the tool is able to quantify the LULC, calculate the average of imperviousness and of CN parameter and estimate the runoff in the watershed, for a given rainfall event.Pages: 3779-378