Districtwise drought climatology of the Southwest monsoon season over India based on standardized precipitation index (SPI)
In this new study IMD examines district-wise and all India drought climatology over India for southwest monsoon season using using Percent of Normal(PN) & Standardized Precipitation Index(SPI).Compares drought climatology based on SPI with that based on PN to show that SPI is a better index for monitoring drought conditions over smaller spatial scales like districts, subdivisions etc.
District-wise drought climatology over India for the southwest monsoon season has been examined first time using two simple drought indices; Percent of Normal (PN) and Standardized Precipitation Index (SPI). The drought indices were computed using long times series (1901-2003) of southwest monsoon season rainfall data of 458 districts over the country. Identification of drought incidences over the country as whole using both PN and SPI yielded nearly similar results. However, the district-wise climatology based on PN was biased by the aridity of the region. Whereas drought climatology based on SPI was not biased by aridity. Thus it was showed that SPI is better drought index for the district-wise drought monitoring. SPI is also suitable for examining break and active events in the monsoon rainfall.