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Floods are the main natural disasters in Brazil, causing loss of life and socioeconomic damage. This work proposes a model for the remote detection of areas that are naturally flood-prone due to the morphometric characteristics of their relief and drainage networks in the Alto Sapucaí River in Minas Gerais, Brazil. The morphometric parameters used were the drainage density, river density, relief ratio, roughness index, maintenance coefficient, form factor and stream surface length. The risk areas had a compactness coefficient of 0.75 and a form factor of 0.56, and both were considered a high risk for floods. The obtained results allowed the identification of a significant predictive equation that suggested a cutoff value of 3.82 for the discriminant function; areas with values under this cutoff were considered naturally more vulnerable to floods occurrences. These areas were corroborated with the emergency maps of the municipalities. The map obtained by the proposed model was compared with the Civil Defense map, and its accuracy, according to the Kappa coefficient, was 0.83, indicating strong similarity between the two maps. [ABSTRACT FROM AUTHOR]

Development and implementation of effective protected area management to reduce deforestation depend in part on identifying factors contributing to forest loss and areas at risk of conversion, but standard land‐use‐change modeling may not fully capture contextual factors that are not easily quantified. To better understand deforestation and agricultural expansion in Amazonian protected areas, we combined quantitative land‐use‐change modeling with qualitative discourse analysis in a case study of Brazil's Jamanxim National Forest. We modeled land‐use change from 2008 to 2018 and projected deforestation through 2028. We used variables identified in a review of studies that modeled land‐use change in the Amazon (e.g., variables related to agricultural suitability and economic accessibility) and from a critical discourse analysis that examined documents produced by different actors (e.g., government agencies and conservation nonprofit organizations) at various spatial scales. As measured by analysis of variance, McFadden's adjusted pseudo R2, and quantity and allocation disagreement, we found that including variables in the model identified as important to deforestation dynamics through the qualitative discourse analysis (e.g., the proportion of unallocated public land, distance to proposed infrastructure developments, and density of recent fires) alongside more traditional variables (e.g., elevation, distance to roads, and protection status) improved the predictive ability of these models. Models that included discourse analysis variables and traditional variables explained up to 19.3% more of the observed variation in deforestation probability than a model that included only traditional variables and 4.1% more variation than a model with only discourse analysis variables. Our approach of integrating qualitative and quantitative methods in land‐use‐change modeling provides a framework for future interdisciplinary work in land‐use change. [ABSTRACT FROM AUTHOR]

In the last decade, the Persistent Scatterer Interferometry - PSI have been largely employed to predict instabilities and failure in open pit mines. The PSI is a powerful technique, which combines radar satellite data in order to detect and monitor tiny surface displacements over vast areas. In the last years, the Sentinel-1 radar mission have produced images of the globe acquired with different spatial and temporal resolutions that are now freely available. In recent years, the footwall slopes of the Riacho dos Machados Gold Mine - MRDM (Minas Gerais state, southeastern Brazil) have recorded large planar failures controlled by foliation planes. Therefore, the focus of this paper is to evaluate a stack of 39 Interferometric Wide Sentinel-1 scenes, spanning from January 2018 to April 2019, acquired in descending orbit geometry, for the detection and monitoring of surface displacements. The results have shown that descending IW Sentinel-1 scenes can be used to provide a broad picture of the Line-Of-Sight - LOS deformation phenomena. In order to monitor the evolution of the deformation phenomena induced by mining activities, LOS deformation maps with millimeter accuracy could be only delivered at least every 12 days. [ABSTRACT FROM AUTHOR]

Introduction: studies reveal that Amazon region is vulnerable to climatic extremes such as droughts, in this context, remote sensing, together with other spatial analysis tools, has been widely used for monitoring environmental activities, including this natural phenomenon, and continuously improving measurements, spatial and temporally. Objective: to monitor the effects of an extreme drought on the hydric seasonality of the Curuaí lake system, Amazon River, Pará state, Brazil; through the use of geotechnologies such as remote sensing and GIS. Methods: the present work made use of a Landsat-5 time series, flow and drought period in 2010; with application of NDWI - Normalized Water Difference Index, and subsequent vectorization of the contour of this water body, to determine the percentage of reduction in the water depth area in the most significant months, and compilation of associated information. Results: The NDWI on the time series showed satisfactory results in enhancing the aquatic surface, allowing the zoning of these areas and comparing their reductive percentage, which showed potentially harmful effects, with a reduction from 1,524 km² to 338, 851 km². Conclusion: The applied index obtained satisfactory results, showing how these geotechnologies, and their information extraction techniques, can be effective in monitoring potentially harmful natural phenomena over the study region; therefore, through more advanced studies, they can be effective for planning strategies to mitigate these impacts on the diverse ecosystems of the Amazon. [ABSTRACT FROM AUTHOR]

Aiming to understand the dynamics of land use and land cover in the municipality of Orizona - Goiás, Brazil, it was sought to understand how the agricultural expansion interfered with the changes in the surface modeling that occurred in the Brazilian Cerrado regions, relating them to the influence of the Agroindustrial Complexes that intensified such modifications. For this, the years 1985, 1995, 2005, 2015, 2018 and 2020 were defined to develop the necessary mappings and to identify local dynamics. The development of this research was based on understanding the dynamics of land use and land cover through the systemic method, using remote sensing and geoprocessing techniques for the survey of the data originated from the acquisition of satellite images, the color composition (RGB), the geometric correction, the segmentation and classification of the images, and finally, the elaboration of the maps. The results of this study showed the gradual expansion of agricultural areas in Orizona during the whole researched period, being related to the development of the modernization of the countryside and the advance of the agricultural frontier in the Cerrado, already staggered by pasturages. In this perspective, it was possible to observe the return of native vegetation areas as a result of the advance of anthropic uses, reducing approximately 42% of the total preserved area, while agriculture increased roughly 160% in the researched period. These aforementioned transformations are happening not only in the municipality of Orizona, but also in practically the entire Brazilian territory, arousing the interest in researching this topic. [ABSTRACT FROM AUTHOR]

In the 1950s, the naturalist Balduino Rambo, anticipating the future of conurbation along the main roads and rail near Porto Alegre/RS, argued that a state tree farm ("horto florestal") existing in the area was maintained as public green area. In this work we assessed the effect on the same tree farm today, when comparing results of surface temperature mapping obtained by image processing from the Landsat TM5 sattelite, with aerial photographs of the same area and with data from weather stations. We found that, on a summer day, surface temperatures into the "horto-florestal" were 8° C cooler than the surrounding urban industrial areas. Thus, Rambo's prophecies are already a reality, because besides from being a disrruption in the urban-industrial landscape, the "horto-florestal" is an island of freshness in the conurbation of the metropolitan area of Porto Alegre-RS. [ABSTRACT FROM AUTHOR]