Computation of the standardized precipitation index (spi) for assessing droughts over india

Nandargi S.S and Aman K

Droughts are extreme meteorological/hydrological events affecting many cultural, social, agricultural and thereby economics of the region affected and the country as well. Analysis of monthly rainfall data for 34 meteorological sub-divisions in India for 1951 to 2015 has been carried out to assess the droughts by computing Standardized Precipitation Index. The SPI values were also analyzed with actual rainfall as well as rainfall deviations from normal for different seasons and on annual scale. The analysis revealed that of the 34 met sub-divisions, 16 sub-divisions during monsoon season and annual are drought prone showing high negative SPI values. The extreme eastern sub-divisions of Arunachal Pradesh and Nagaland, Manipur, Mizoram, Tripura did not record severe droughts while North and South Interior Karnataka sub-divisions in the Peninsular India recorded six severe drought years. There was a relation between SPI and negative rainfall deviations, but the magnitude of SPI values did not indicate the severity of drought situation. The results of the study will be useful to drought monitors, water resources planners, and too agriculturists.

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