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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.

The use of uncontrolled fire by human beings associated with climate conditions favorable to burning has caused social, economic and environmental damage in different parts of the world. The objective of the present study was to evaluate the variations in the occurrence of fire in Southern Region of Brazil caused by the seasonal characteristics of the years. We also sought to highlight the vegetation coverings most affected by fires within each year assessed and among the different ENSO events. Fire products from the MODIS were associated with meteorological elements and vegetation cover data, in addition to evaluating Carbon emission data made available by GFED. The correlation between the meteorological elements and fire was obtained by Spearman's non-parametric approach. Additionally, Mann Kendall's statistical test was performed with the harvested area extensions of three temporary agricultural crops (Maize, Soybean and Sugarcane) over 28 years. Fire in Southern Brazil correlates mainly with reduced rainfall and relative air humidity together with increased atmospheric pressure and increased wind speed. The periods under the effect of the cold phase of the phenomenon (La Nina) presented 26% to 114% more fire foci than those under the hot phase (El Nino). La Ninas also showed 7% to 77% more burned area than El Ninos. La Nina events emitted more carbon into the atmosphere than El Nino, and the greatest difference was observed between La Nina 2007/2008 (1.51 Tg) and El Nino 2015 (0.65 Tg). The vegetation covers most affected by the fire were those related to agricultural activity. Mann Kendall's statistics indicated that Sugarcane, an agricultural crop with flammable straw, showed a tendency to expand in the state of Parana between 1990 and 2018. Intra and inter-annual atmospheric variations and the mosaic of different vegetation covers determined the fire pattern in the study area over the period studied.