Evaluation of the Rayalseema Meteorological Subdivision’s Drought Using Multiple Drought Indices

Abstract

Abstract Drought is the most prominent natural disaster, which affects various parts of the globe. It is not simply the lack of rainfall, but also how unevenly it occurs during the season, how long the lack of rainfall has lasted and how it has impacted the agriculture, economy and the way of life in the region. The meteorological conditions of a region directly impact various water requirements and are linked to hydrologic, agricultural and socio-economic drought conditions. Thus, it becomes crucial to monitor and characterize meteorological drought of the region to adopt suitable water management practices. The purpose of this research study is to evaluate the meteorological drought conditions over Rayalseema meteorological subdivision of India using multiple drought indices employing historical precipitation (PRCN) and temperature (TEMPR) data obtained from Indian Meteorological Department (IMD) at a resolution of 1°x1°. Three different meteorological drought indices namely, Standardized Precipitation Index (SPI), Reconnaissance Drought Index (RDI) and Standardized Precipitation Evapotranspiration Index (SPEI) have been utilized to incorporate major meteorological variables to account for varying assessment periods of 1, 3, 6, 9,12 and 24 months. The results show that an increase in the number of identified moderate and severe categories of drought events increase with the assessment periods for all the indices used in this study. The severe drought years have been found to be quite frequent post 1980’s as 1986, 1987, 1992, 1994, 1999, 2002, 2004, 2009 and 2011. The Modified Mann Kendall test has been carried out for all the drought indices (SPI, RDI and SPEI) across varying assessment periods and it shows a positive trend for SPI and RDI while a negative trend is seen for SPEI. It may be due to continuous decline of precipitation and corresponding increase in the maximum temperature making the region semi-arid. For the overexploited water resources in Rayalseema, this type of research is critical for analyzing meteorological droughts, which will be extremely valuable for water resource administration and planning in the region.