Analysis of Drought Investigation Using Standard Precipitation Index (SPI) of Historical Rainfall Data (1979-2013) Under Temperate Conditions Over Anand, Gujarat (India)

Abstract

Drought is a naturally occurring event caused due to deficiency in precipitation over an extended period of time. It is a slow-onset, creeping natural hazard that affects continuously all parts of the world. It occurs in all climatic zones such as high as well as low precipitation areas and causes high economic and social losses around the world. Droughts are generally measured in terms of deficiency in the rainfalls or streams flows below a predefined reference level. The magnitude of departure from the reference level during a drought spell is known as the severity of drought. Droughts are occurring in different regions of the world with increased frequency and severity. In this study, temporal pattern of droughts was analyzed in the Anand Station using SPI approach. Monthly precipitation data from 1979 to 2013 were used to compute Standardized Precipitation Index (SPI) values. The computation of SPI series was done for short as well as intermediate time scales. Analysis of SPI values were done to study the temporal patterns of drought occurrence. The drought severity and duration were also estimated. From the analysis, it was observed that in the years 1980, 1984,1985,1986,1987, 1989, 1991,1992,1993,1995, 1999,2000,2001,2002 and 2009 drought occurred in the area in Anand station. Extreme drought occurred in the year 1987 when the SPI value was -2.27. Also, SPI in the severe and extreme drought years indicate only moderate dryness instead of extreme dryness.