Analysis of meteorological drought at New Delhi using SPI

Abstract

A study was conducted to analyse the frequency and temporal trend of standardized precipitation index (SPI) at IARI, New Delhi station during early kharif (June-August), mid kharif (August and September), late kharif (September and October) and whole kharif (June-October) from 1951 to 2009. SPI was calculated at four time scales, i. e., trimonthly, bimonthly AS, bimonthly SO, and pentamonthly corresponding to early, mid, late and whole kharif seasons, respectively. There were five years with moderate drought (1979, 1986, 1987, 1997, 2009) and three years with extreme drought (1951, 1989, 2002) during the early kharif. During the mid kharif, there were seven years with moderate drought (1951, 1953, 1954, 1986, 1989, 1999, 2006), two years with severe drought (1974, 1981) and one year with extreme drought (1979). During the late kharif, four years experienced moderate drought (1974, 1979, 1982, 2002), three years severe drought (1953, 1987, 1994), and two years extreme drought (1952, 1968). The whole kharif season experienced three moderate drought years (1952, 1979, 1997), three severe drought years (1986, 1987, 2002), and two extreme drought years (1951, 1989). There was no temporal trend in the rainfall amount or its distribution at the last 59 years at the IARI New Delhi station. It can be concluded that meteorological drought has nearly the same frequency for early, mid, late and whole kharif seasons in this station. Results suggest that rainfall variability and magnitude has not changed significantly at Delhi in the recent past though Delhi has seen significant land use/cover changes during this period.