by Puja Sahu, P K Mohanty, S R Padhi & K C Gouda
Drought in Odisha, India, varies significantly due to its diverse physiographical features, such as orography, river basins, lakes, coastlines, and the Eastern Ghats, which influence rainfall distribution and drought vulnerability. Understanding and interpreting these rainfall patterns is essential for inferring regional rainfall variability for drought conditions, which in turn affects sectors like agriculture, health, energy, and disaster management. This study aims to analyze and quantify regional rainfall variability for drought assessment, focusing on identifying suitable indices for monitoring drought at the block and district levels. Using long-term block-level rainfall data, five key drought indices were evaluated: Precipitation Concentration Index (PCI), Standardized Precipitation Index (SPI), Effective Drought Index (EDI), Deciles Index (DI), and Percentage Departure (PD). Statistical analyses were conducted to assess the performance of these indices in capturing rainfall variability across monthly and daily timescales. The study explored how the indices reflect drought severity in districts with varying geographic conditions. PCI was effective for rainfall distribution, while SPI and EDI were the most reliable for monitoring extreme droughts. In contrast, DI and PD did not align well with observed data. The EDI showed significant drought impacts in the blocks of Jajpur, Khordha, and Koraput, highlighting the need for targeted agricultural interventions. SPI and EDI provide robust tools for assessing drought in Odisha, particularly for disaster management and water resource planning at block, district, and state levels. The study's findings offer critical insights for managing drought in vulnerable regions.