Spatiotemporal Dynamics of Precipitation and Drought Events in the Amazon Region of Mato Grosso, Brazil
Climate change; rainfall variability; meteorological drought; SPI; SPEI.
This study evaluated rainfall variability and the dynamics of drought events in the municipality of Alta Floresta, Mato Grosso, using historical climate series from 1990 to 2025 obtained from the ERA5-Land reanalysis dataset. Precipitation and air temperature variables were analyzed using the climatic indices SPI (Standardized Precipitation Index) and SPEI (Standardized Precipitation Evapotranspiration Index) at 3- and 6-month temporal scales, in addition to the Mann-Kendall trend analysis. The results revealed high interannual rainfall variability, with reductions in precipitation volumes and an increase in the frequency, intensity, and duration of drought events over recent decades, especially between 2022 and 2024. The SPEI showed greater sensitivity in detecting severe droughts due to the incorporation of potential evapotranspiration, demonstrating that increasing temperatures intensified the regional water deficit. A significant trend toward the prolongation of the dry season and increased rainfall irregularity was also observed, with direct implications for rainfed agricultural systems such as soybean and second-crop maize production. The results indicate that Alta Floresta is experiencing an intensification of climate extremes, reinforcing the need for adaptive strategies focused on conservation soil management, climate monitoring, and increasing agricultural resilience in the face of global climate change.