Spatio-temporal analysis of rainfall extremes and drought variability in the Tel basin, Odisha, India, under changing climate

Climate change has significantly influenced temperature and rainfall patterns, disrupting hydrological cycles and increasing extreme weather events. This study analyses spatial and temporal variations in rainfall trends and extreme climatic indices in the Tel Basin, Odisha, India, from 1981 to 2021. Rainfall trends were assessed using the Mann–Kendall test and Sen’s slope estimator, while extreme climatic indices were evaluated using the Climpact tool. Drought variability was examined using the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI), accounting for the role of temperature in drought intensification. The results reveal pronounced spatial heterogeneity in rainfall trends. Monsoon rainfall shows increasing trends (up to 17.48 mm/decade), while pre-monsoon rainfall is declining (up to −2.64 mm/decade). Heavy rainfall events (R20mm, R30mm) are rising, whereas consecutive dry days (CDD) have increased by ~ 5 days/decade and consecutive wet days (CWD) have decreased by ~ 3 days/decade. Drought analysis shows that SPI-6 exhibits a weak increasing trend (Sen’s slope = 0.001), whereas SPEI-6 indicates a stronger drying pattern (Sen’s slope = − 0.005), highlighting the influence of rising temperatures. Temperature extremes, such as TXx (~ 0.02 °C year⁻¹), along with an increase in tropical nights, indicate intensified warming, which enhances evapotranspiration and increases agricultural water stress. The results stress the urgent need for adaptive water resource management, climate-resilient agriculture, and improved irrigation planning in the Tel Basin to combat the growing climate-induced vulnerabilities.