Assessment of drought conditions in arid steppe hot regions of Karnataka, India, using meteorological indices and geospatial approaches

Drought is a main climatic hazard affecting water resources and agricultural activities in semi-arid areas. This study evaluated the spatiotemporal variability of drought in the hot semi-arid areas of Karnataka, India, using the Standardized Precipitation Index (SPI), Standardized Precipitation Evapotranspiration Index (SPEI), and Rainfall Anomaly Index (RAI). Meteorological data from 11 grid stations covering 1979 to 2019 were analysed, with the indices calculated at 3-, 6-, and 12-month timescales. Geographic Information System (GIS) methods and Inverse Distance Weighting (IDW) interpolation remained employed to map the spatial distribution of drought circumstances and categorize drought-prone parts. SPI-3 and SPEI-3 reflected short-term precipitation variability, while SPI-6 and SPEI-6 indicated prolonged rainfall deficits and the effect of atmospheric evaporative demand. SPI-12 and SPEI-12 exposed longer-term drought conditions related with sustained rainfall lacks. The RAI study identified 27 years with negative precipitation anomalies, indicating below-normal rainfall. The major drought years recognized were 1983, 1992, 2003, 2016, and 2017, with the 2017 event particularly evident in the SPEI investigation. Mulabagilu recorded the highest annual rainfall of 1447.01 mm in 2015, while Gudibande recorded the lowest annual rainfall of 68.92 mm in 1982. GIS-based spatial investigation identified Gudibande, Bagepalli, and Chikkaballapura as comparatively drought-prone areas. The combined meteorological and geospatial valuation highlights local differences in drought conditions and delivers spatial information for drought monitoring and water resource planning.