Dynamics of fire risk under the effect of El Niño in a landscape of the caatinga biome in Petrolina, Pernambuco

The aim of this work is to assess the influence of El Niño on the dynamics of fire risk in the landscape of the Caatinga biome in Petrolina-PE, monitoring the risk of fire in relation to the severity of El Niño. Landsat-8 satellite images of the municipality of Petrolina-PE were obtained from the USGS website. The following criteria were adopted for the selection of images: Images from the years 2015 to 2020, considering the period from August 1st to December 31st, times when there is little rainfall, few clouds and high temperatures due to the warmer months. The tool used to process the data was QGIS software, an open-source program. Six fire risk maps were generated over the course of these years. The AHP methodology, widely used by various authors, was used to create the forest fire risk maps. In this methodology, eight variables were considered: hypsometric map, land use and occupation, slope orientation, declivity, road system, precipitation, surface temperature and normalized difference vegetation index. According to the results, a temporal analysis of fire risks was obtained which shows that from 2015 to 2018 there was a continuous increase, while in 2019 and 2020 there was a reduction in the risk of fires. Between these last years, there was an El Niño and a La Niña event, and in 2020 there was the pandemic, resulting in few transportation flows on the roads, causing a low risk of fires.