Use of Meteorological Data for Identification of Drought

Abstract

Drought has been called a creeping disaster because of the way it develops slowly. It can be defined according to meteorological, hydrological and agriculture criteria. In the present study, meteorological data i.e., monthly rainfall data from different rain gauges stations were used for identification of drought. Standardized Precipitation Index (SPI) values were generated based on Gamma distribution of precipitation data for 32 years (from 1985 to 2016) for Ananthpur district of Andhra Pradesh in India. Comparison of SPI, with actual rainfall and rainfall deviation from the mean indicated that SPI values underestimate the intensity of dryness/wetness when the rainfall is very low/very high respectively. This shows that the range of SPI values of the high rainfall district indicated better stretching, compared to that of the low rainfall district. SPI indicated deviation from normal probability in the lower and upper ranges. Therefore, it is suggested that SPI as a stand-alone indicator needs to be interpreted with caution to assess the intensity of drought.