Spatiotemporal rainfall patterns in a semiarid region in Brazil

ABSTRACT Water scarcity is a growing concern globally, driven by uneven spatial and temporal distribution of water resources. This is especially true in semi-arid regions. This study investigated rainfall variability in the Minas Gerais portion of the Atlântico Leste Hydrographic Region (RHAL-MG), which overlaps partly with Brazil's semi-arid region and areas at risk of desertification. We analyzed precipitation data from 33 stations between 1980 and 2022 using statistical methods and the Standardized Precipitation Index (SPI). The results revealed distinct rainfall patterns in RHAL-MG, closely aligning with the boundaries of polygons corresponding to semiarid and desertification prone zones within the study area. Rainfall exhibited a seasonal pattern, with the rainy season predominantly occurring between October and March. However, the amount and intensity of rainfall varied across the regions segmented in the spatial analysis. No statistically significant pluviometric trends were identified in 76% of the stations, while 24% showed a significant trend of decreasing rainfall volume.