Meteorological Drought Study Through SPI in Three Drought Prone Districts of West Bengal, India

Abstract

Deficiency in rainfall introduces drought phenomena with temporal and spatial variability in terms of intensity and magnitude. Study of drought in different scales is necessary for successful planning in a country such as India, where agricultural sector contributes highest in economy. Drought indices (DI) have a tool to quantify the drought nature and express a single digit which is helpful to recognise a drought character. Standardized Precipitation Index (SPI) is a tool to quantify the drought characteristics, widely used for its simplicity and variable approaches to dignify a drought. Therefore, the present study deals with SPI to analyse drought phenomena in pre-monsoon, monsoon, post-monsoon and monthly time steps in three relatively drought prone districts (Purulia, Bankura, Midnapore) of West Bengal in India of rainfall data of 117 years (1901–2017). From SPI values, drought frequency is analysed using Gumbel’s type 1 distribution and trend is calculated using Mann–Kendal test (M–K test). Occurrence of drought with negative SPI values is frequent in these districts with increasing dry events and decreasing wet and normal event. More intensive study in hydrological and agricultural drought is necessary to implement any plan with this increasing aggravation of drought.