Correlação entre distintos índices espectrais de vegetação e focos de calor no bioma Cerrado
Wildfires are common in most of the vegetated areas of the world, playing an important role in the ecosystems and in climate. The tropical savannas are the most frequently burned ecosystems due to the vegetation characteristics. In the Cerrado biome (Brazil), besides being a natural occurrence, fire is an important tool in the land-use and land-cover change process occurring since the 1970s. Considering the dimension of fires and the study area, remote sensing is the most effective source of data for studying fire patterns in the Cerrado, highlighting the MODIS sensors, which since 2000 provide data about the surface and atmosphere dynamics. Furthermore, one of the most important variables for the occurrence of fires is the vegetation condition, being vegetation indexes derived from MODIS, such as NDVI, VCI, EVI and NDWI, effective for providing information about this variable. However, the performance of these indexes varies according to the vegetation analyzed, once fire characteristics depends on the vegetation type. In the context, this study aims to analyze the correlation between active fires and the previous cited vegetation indexes estimated from MODIS in order to estimate which index better represent the susceptibility of vegetation to the occurrence of fires in the Cerrado. Results show that active fires are concentrated during dry season (May to September) in the north and midwest of the biome, and are correlated with the vegetation indexes, which all showed the same temporal pattern. VCI was the better correlated index with active fires in the Cerrado (r = -0,817).