Climate Extremes and Fire Behavior in the Brazilian Cerrado: A Multi-Years Assessment (2012-2023)

Abstract

This study examines the influence of simultaneous drought and heatwave events on fire dynamics in the Brazilian Cerrado biome between 2012 and 2023. Monthly and annual analyses of fire radiative power (FRP), fire radiative energy (FRE), heatwaves, and droughts were carried out based on data from 172 meteorological stations. Temperature and precipitation data were obtained from the Brazilian National Institute of Meteorology (INMET), while FRP data were derived from VIIRS sensors onboard the NOAA-20 and Suomi NPP satellites. Droughts were identified using the Standardized Precipitation Index (SPI) at 1- and 6-month timescales. The results show that periods with higher heatwave occurrence coincided with increased fire activity, especially in September, which recorded the highest FRP (similar to 10(3) MW/h), 1,346 heatwave events, and 1,825 heatwave days. FRE peaks were observed between July and October, particularly in July (similar to 10(9) MJ). The most intense drought conditions (SPI-1 and SPI-6) were concentrated in July and August. Statistical analysis revealed a strong positive correlation between heatwave frequency (CTX90) and FRP (r = 0.89), as well as negative correlations between FRP and SPI-1 (r = -0.47) and SPI-6 (r = -0.50). These results highlight the significant role of simultaneous extreme climatic events in fire dynamics and reinforce the importance of understanding these events to better assess and mitigate their impacts in the region. [GRAPHICS] .