Meteorological drought dynamics and climatic interactions in the arid and semi-arid regions of western India.

Abstract

Climate change has heightened uncertainties in climatic behaviour, resulting in an increase in extreme events like floods and droughts, which significantly impact water resource management and agricultural practices. In India, over 80 % of agricultural land relies on rainfed systems, making it particularly vulnerable to uncertainties in rainfall, often leading to crop failures in the arid and semi-arid regions of western India. This study utilizes the Standardized Precipitation Evapotranspiration Index (SPEI) to analyze drought characteristics-frequency, duration, severity, and intensity-using India Meteorological Department (IMD) based rainfall and temperature data from 1981 to 2023 across five agro-climatic zones. Seasonal and annual drought trends were assessed with the Modified Mann-Kendall test, while cross-wavelet transform analysis explored the connections between global climatic phenomena and regional droughts, focusing on atmospheric drivers like the El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD). Findings indicate that over 35 % of the study area experiences long-term drought (SPEI12). Short-term drought (SPEI01) is prevalent in the Central Plateau and Hills (Z02), whereas long-term droughts primarily affect the Gujarat Plains and Hills (Z04) and the Western Dry Region (Z05). A statistically significant increasing trend in drought occurrence (at the 95 % confidence level) was observed across all seasons except the monsoon. Throughout most of the study region-excluding a few scattered pockets-the monsoonal trend showed a positive SPEI, indicating an overall increase in rainfall during the monsoon season since 1981. The analysis also revealed a significant correlation between drought events and the El Niño-Southern Oscillation (ENSO) phenomenon, with droughts being more strongly influenced by different ENSO phases than by the Indian Ocean Dipole (IOD). Furthermore, the study identified distinct spatial patterns of drought occurrence, trends, and their global climatic drivers across various agroclimatic zones in India's arid and semi-arid regions. These results underline the need for evidence-based policies to mitigate drought impacts and promote sustainable development in India's dry regions.