Drought assessment through multiple indicators for Karnataka state, India.

Drought indices are imperative for determining the occurrence and impact of drought on crop production and society. Selecting appropriate indices to comprehensively assess the stress conditions is critical to analyze their effects on crops. The current study focuses on a comparative analysis of various indicators including the Standardized Precipitation Index (SPI), Standardized Water level Index (SWI), Standardized Reservoir Level Index (SRLI), Moderate Resolution Imaging Spectroradiometer (MODIS) Normalized Difference Vegetation Index (NDVI), NDVI Anomaly, Vegetation Condition Index (VCI), and Evaporative Stress Index (ESI). The spatio-temporal pattern of these indices and their relationship with detrended Kharif foodgrain production anomaly (DPA) were examined for the Kharif crop growing season from 2001 to 2019. The results revealed that the region experienced drought conditions 15 times, with SPI-6 and ESI showing the strongest correlations with DPA - correlation coefficients of 0.76 and 0.74, respectively. To assess the percentage area under drought (AUD) values, the total pixels classified as drought based on threshold values for each index were calculated and the results were compared with figures declared by the state government. SPI-3, SPI-6, VCI, and ESI significantly captured the extent of drought yielding correlation coefficients of 0.75, 0.82, 0.62, and 0.74 respectively. Observations from this study may be used to determine the most critical indicators for drought monitoring.