Trends and variability of droughts over the Indian monsoon region

Abstract

Drought characteristics for the Indian monsoon region are analyzed using two different datasets and standard precipitation index (SPI), standardized precipitation-evapotranspiration index (SPEI), Gaussian mixture model-based drought index (GMM-DI), and hidden Markov model-based drought index (HMM-DI) for the period 1901–2004. Drought trends and variability were analyzed for three epochs: 1901–1935, 1936–1971 and 1972–2004. Irrespective of the dataset and methodology used, the results indicate an increasing trend in drought severity and frequency during the recent decades (1972–2004). Droughts are becoming more regional and are showing a general shift to the agriculturally important coastal south-India, central Maharashtra, and Indo-Gangetic plains indicating higher food security and socioeconomic vulnerability in the region.

Keywords

• Drought index
• Hidden Markov model
• Standard precipitation index
• Gaussian mixture model
• Indian monsoon
• Uncertainty analysis
• Drought vulnerability