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The Jurua Watershed region, an important tributary of the Amazon River, lacks scientific information related to climate and environmental variables. In this sense, this study intends to analyze the environmental dynamics of the Jurua Watershed in the Amazon. We used monthly weather data derived from Reanalysis 2. The products fire foci, vegetation index and surface water index derived from the MODIS sensor for a monthly time series from 2001 to 2018. The ARIMA model was used to simulate future changes from NDFI. The lowest rainfall years of the series were 2005, 2010 and 2016 also observed for soil moisture in 2005 and 2016; the most rainfall years were 2009 and 2014, with the highest values of flooded areas in January, 23,772 km2. The highest concentration of fire foci occurred in August and September, coinciding with the lowest NDFI values found (1421 km2 and 890 km2), with the years 2005 and 2010 with highest fire foci. The EVI showed higher values from October to December with values close to 0.57, the lowest values in June and July (0.50). The years 2009 and 2015 showed largest flooded area records, 2005 and 2010 the lowest records. The PCA pointed out the rain as the variable of greatest influence in the basin with 0.98, followed by hot flashes with − 0.90. NDFI was highly correlated with rainfall and ARIMA modeling allowed the generation of a reliable future scenario and a significant downward trend in flooded areas by 2030.

In recent years, Brazil has become a major global contributor to the occurrence of national fires and greenhouse gas emissions. Therefore, this study aimed to evaluate the fire foci data of the past 20 years to determine their relationship with climatic variables in various Brazilian regions. The variables evaluated included fire foci, land surface temperature, rainfall, and standardized precipitation index, which were obtained via remote sensing from 2000 to 2019. The data were subjected to trend analyses (Mann-Kendall and Pettitt tests) and a multivariate analysis of canonical variables for evaluation. The results showed that the Midwest and North regions had the highest occurrence of fire foci throughout the study period, and that the North region had the highest accumulated annual rainfall. Thus, these regions require specific public policies to prevent future fires. Overall, the Midwest, Southeast, and South regions exhibit significant increasing fire foci tendencies. Our results reveal that this trend is related to the El Niño-Southern Oscillation (ENSO) phenomena, which alter climatic variables such as precipitation, land surface temperature, and the standardized precipitation index. Finally, the sugarcane growing area had a significant linear relationship with fire foci in the Southeast region, especially in the state of São Paulo, the major national sugarcane producer.

The process of anthropization of the Cerrado has generated diverse environmental liabilities, such as a reduction in biodiversity, degradation of water resources, and alteration of the quality and quantity of water in local water bodies. Thus, the objective of this study was to evaluate the evolution natural regeneration processes of environments under anthropic influences in relation to variations in climatic conditions and the recovery of environmental services in watersheds in the Cerrado. For this purpose, the watershed in the Federal Institute of the Triângulo Mineiro (IFTM) Uberaba-MG Campus was used. The dynamics of natural regeneration were evaluated using the vegetation index (MOD13Q1) and gross primary production (GPP; MOD17A2), which were correlated with the climatic variables and waterflow in the watershed. The characteristics of vegetation dynamics, climatic variables, and flow were determined by descriptive analysis and deviations, and the relationship among variables was determined using multivariate analysis. The process of natural regeneration presented a positive pattern of vegetation expansion in environments under anthropic influence in the Cerrado, which was due to the seasons, time, and climatic elements, and was observed through the temporal dynamics of normalized difference vegetation index NDVI and GPP in the watershed. Natural regeneration is determined by two climatic elements rain and air temperature with rain driving vegetation growth, thereby directly influencing the dynamics of natural regeneration and the recovery of environmental services.

Forest canopies have an important influence on the global climate balance. Through the analysis of the temperature of the canopy, it is possible to infer about the physiological aspects of the plants, helping to understand the behavior of the vegetation and, consequently, in the environmental monitoring and management of green areas. This study aims to validate the MOD11A2 V006 product from canopy surface temperature data obtained by an infrared radiation sensor. For the validation of the MOD11A2 product, a comparative analysis was performed between the land surface temperature (LST) data, obtained by the MODIS sensor, and the canopy temperature data, obtained by the SI-111 infrared radiation sensor coupled to the Itatiaia National Park (PNI) micrometeorological tower. Meteorological variables and land surface temperature collected from January to December 2018 in the PNI were also analyzed. The results reveal that the MOD11A2 product overestimates the canopy temperature in the daytime (MB ranging from 1.56 to 3.57 °C) and underestimates in the night time (MB ranging from - 0.18 to - 4.22 °C). During daytime, the months corresponding to the dry season presented a very high correlation (r = 0.74 and 0.86) and the highest values for the Willmott index (d = 0.70 and 0.64). At nighttime, the MOD11A2 product did not present a good performance for the LST estimation, especially in the rainy season. Therefore, we observed that the MOD11A2 product has limitations to estimate the land surface temperature and that possible changes in the algorithm of this product can be performed for high atmospheric humidity conditions.

The need to validate the quality of evapotranspiration estimates is essential for this parameter which has extended its use. For this, it is necessary to evaluate both new remote sensing products that expand the areas of estimated evapotranspiration and empirical equations that provide estimates with different data requirements. In order to examine this problem, the present study compared the estimates of evapotranspiration obtained by remote sensing of the MOD16A2 product and seven empirical equations with the estimates obtained through the FAO-56 reference method, with data obtained from six meteorological stations in the State of Rio de Janeiro, Brazil. Data cover the period from 2007 to 2013, which contains different phases of the El Nino–Southern Oscillation phenomenon. The methods proposed by Valiantzas were those that obtained the best performances when compared with FAO-56 with R2 over 90%. The non-parametric analysis of Mann-Kendall for the six seasons was mostly not significant; only the station of Resende showed a tendency of significant growth during the El Nino episode (Z = 0.283 and p value = 0.050). The mangrove and forest classes were the ones that obtained the highest averages (3.75 mm d−1 and 3.62 mm d−1), where the gradient of evapotranspiration can be observed in the South-Northeast portions. The MOD16A2 orbital product was inferior to the methods that used surface meteorological station data.

The objective of this work is to evaluate the occurrence of fire foci during the severe drought that occurred in 2005 in the State of Amazonas. The study was conducted in the State of Amazonas, which is inserted in the northern region of Brazil. The main types of vegetation are Igapo Forest, Varzea Forest and Terra Firme Forest. Kernel density was used to spatialize fire foci to quantify them in seven classes of land use and cover (forest, pasture, exposed soil, urban area, pastoral agroforestry system, agroforestry system and agriculture). Through the regression analysis, the relation among the number of fire foci and four meteorological variables was obtained: rainfall, evapotranspiration, relative humidity and average air temperature. Forest and pasture classes were those with the highest number of fire foci corresponding, respectively, to 58 and 37% of the total number of foci. This can be explained by the greater representativeness of these classes in the State and by the high degree of soil exposure in the case of pasture. The number of fire foci was higher in the dry season, covering approximately 85% of the total fire foci. The variable that had the greatest influence on the occurrence of fire foci in the dry season was evapotranspiration. The study puts on alert the vulnerability of the State of Amazonas to the occurrence of fires and may also suggest actions to mitigate carbon emissions and biomass stock. Research like this one may provide subsidies to region’s managers in an attempt to preserve forest areas and a greater controlling in priority areas considered very high.

Cerrado is the second-largest Brazilian biome and an important area for nature conservation. However, little is known about the distribution of forest species in anthropized areas undergoing natural regeneration. Understanding the dynamics of ecological succession is fundamental to the decision-making process regarding revegetation of anthropic areas in the Cerrado. Thus, this study aimed to evaluate the phytosociological patterns of natural regeneration in areas anthropized by agricultural uses in the Cerrado in different soil and environmental conditions. For this purpose, the study was performed in an anthropized area that has been protected from anthropic actions since 2002. A floristic survey of forest species was carried out, and soil samples were collected at depths of 0–5, 5–10, and 10–20 cm to determine the physical and chemical properties of the soil. The distribution of forest species with respect to the soil characteristics was determined using multivariate analysis. The distribution of the forest species was shown to be influenced by the soil properties and the degree of succession of the vegetation. Furthermore, the natural regeneration process resulted in an improvement in the chemical properties of soils in the Gleysol class. This pattern is related to the slow decomposition of organic matter, being associated with an environment that has greater water availability and, consequently, less nutrient loss from leaching during the cycling mechanisms responsible for the return of nutrients to the soil.

This study aimed to analyze the spectral trend of vegetation with rainfall in El Niño-Southern Oscillation events (ENSO) in the Atlantic Forest, Brazil. Monthly rainfall data were collected from 85 conventional meteorological stations (EMC), data from the Enhanced Vegetation Index 2 (EVI2) and ENSO events (El Niño, La Niña, and Neutral) in the period from 2001 to 2013. Afterwards, state cluster analysis was performed using the results of non-parametric tests. The Mann-Kendall (MK) non-parametric test did not identify a trend pattern in rainfall distribution in the Atlantic Forest. The results for EVI2 by state and region showed that the trend is decreasing in the Northeast Region, except for the states of Alagoas and Pernambuco. Southeast region showed an increasing trend of EVI2 (except for Rio de Janeiro and São Paulo), while the South region showed a decreasing trend. In the Midwest, the trend was significantly decreasing. In the prognosis elaborated for the future, the regions with significant declines of the vegetation were the Northeast and Midwest. This study shows that the Atlantic Forest in some regions of Brazil has been suffering from the growing urbanization process and there is a trend of soil degradation.

We evaluated the distribution, percentage, and homogeneous regions of fire foci in Brazil over 1998–2011. Included are numbers of fire foci by regions and states as well as their seasonal and monthly variations, with emphasis on human activities and their relationships with producing systems and rainfall inhibitors. We used data from forest fire meteorological satellites, obtained from the Centro de Previsao do Tempo e Estudos Climaticos. Evaluation of regional fire foci distributions gave 37.15 % for the central west and just 1.75 % in the south. Brazilian regions with the highest densities of forest fires per unit area were the northeast, central west, and north. Lowest densities were in the north, southeast, and south. The states of Mato Grosso, Para, Maranhao, Bahia, Rondonia, and Tocantins had the greatest numbers of fire foci during our study period. The Federal District and the states of Sergipe, Espirito Santo, Rio de Janeiro, Rio Grande do Norte, and Alagoas had the smallest numbers. Spring (62.2 %) and winter (28.7 %) had higher frequencies than summer (6.7 %) and autumn (2.7 %). A clustering technique showed three homogeneous regions of fire foci in Brazil. The regional grouping technique showed the influence of synoptic systems and large-scale patterns of fires in the country. In addition to the use of NOAA-12 satellite images for monitoring Brazilian fire foci, orbital platforms such as MMODIS-01D and T-AQUA can be used. Finally, anthropogenic activities (deforestation, agriculture, livestock, mining, and industrial) and the variability of meteorological systems affected the fire increase during the study period.