The dynamics of meteorological droughts over a semi-arid terrain in western India: A last five decadal hydro-climatic evaluation

Abstract

Western Gujarat is one of the regions of India which has suffered from frequent drought events once every three years. High monsoonal variability on account of erratic rainfall, over-exploited aquifers, and poor groundwater recharge conditions in basaltic terrain are few reasons for drought spells over the study area. The study focuses on understanding more on drought regime and its patterns in the seven districts of Gujarat and its close linkages with the partial arid state therein using selected indicators of SPI, SPEI, rainy days, and daily rainfall intensity. However, if there persist events like drought or famine due to scanty or irregular rainfall, a study is deemed necessary to identify, confirm and characterize drought. The present study is largely focusing on such a scene where drought impacts over the Saurashtra region are assessed by evaluating climatic data of rainfall and temperature for each year of study. The deficit rainfall regime is explored for occurrences of a drought of varying severity between 1969 and 2018. The positive and negative patterns of the water regime are explored, and the anomalies are detected, signifying relationships among rainy days and drought-affected areas. Drought dynamics is detected for 17 years of drought occurrences with three years- 1972, 1987, and 2012 as major drought years and extreme drought was found to be widespread during post-monsoon months. The current work focuses on identifying and classifying drought spells with their severity extent for studying impacts of drought on the hydrological regimes in a longer perspective with SPI values below −1.5 in western India.