Spatiotemporal analysis of meteorological drought variability in the Indian region using standardized precipitation index

Abstract

Grid (1° latitude × 1° longitude) level daily rainfall data over India from June to September for the years 1951-2007, generated by the India Meteorological Department, were analysed to build monthly time series of Standardized Precipitation Index (SPI). Analysis of SPI was done to study the spatial and temporal patterns of drought occurrence in the country. Geographic spread of SPI-derived Area under Dryness (AUD) in different years revealed the uniqueness of the 2002 drought, with widespread dryness in July. Mann-Kendall trend analysis and moving average based trends performed on the AUD indicated an increasing trend in July. The area under moderate drought frequency has increased in the most recent decade. Ranking of years based on Drought Persistency Score (DPS) indicated that 1987 was the most severe drought year in the country. The results of the study have revealed various aspects of drought climatology in India. A similar analysis with the SPI of finer spatial resolution and relating it to crop production would be useful in quantifying the impact of drought in economic terms. © 2011 Royal Meteorological Society.