Drought characterization over India under projected climate scenario

Abstract

The study evaluates the drought characteristics in India over projected climatic scenarios in different time frames i.e., near-future (2010-2039), mid-future (2040-2069), and far-future (2070-2099) in comparison with reference period (1976-2005). Standardized Precipitation Evapotranspiration Index (SPEI), a multiscalar drought index was used owing to its robustness in capturing drought conditions while accounting the temperature. Gridded rainfall and temperature data provided by India Meteorological Department (IMD) was used to perform bias correction of 9 Global Climate Models (GCMs) from Coupled Model Intercomparison Project Phase 5 (CMIP5) project. Quantile mapping was used to correct the daily rainfall data at seasonal scale whereas daily temperature data was corrected at monthly scale. Multi-Model Ensemble (MME) was prepared for different homogeneous monsoon regions of India, namely Hilly Regions (HR), Central Northeast (CNE), Northeast (NE), Northwest (NW), West Central (WC), and Peninsula (PS). Taylor diagram statistics were used for the preparation of MME. The regional climate cycle obtained from MME was found to be in good agreement with observed cycle derived from IMD data. The Mann-Kendal trend test was employed to detect the trend in drought severity and magnitude whereas L-moments based frequency analysis was used to assess the magnitude of extreme drought severity under different time frames. The study reveals an increasing trend in drought severity, duration, occurrences, and the average length of drought under warming climate scenarios. Furthermore, the area under ‘above moderate drought’ (i.e., severe and extreme drought combined) condition was also found to be increasing in projected climate.