Characterization of meteorological drought over a dryland ecosystem in north western India

Abstract

Droughts are the greatest and the most recurrent climatic hazard that frequently strikes India, fetching serious water deficiencies, economic failures and unfriendly social events. An investigation of regional droughts can help policy makers in achieving the goals of sustainable governance of water resources. Hence, this study examined the characteristics of meteorological drought over the dryland ecosystem of Rajasthan state in north western India, based largely on diurnal rainfall statistics of 33 stations for the period 1961–2017. For investigating meteorological drought, standardized precipitation index (SPI) was computed at various time spans such as early (June to August), mid (August to September), late (September to October) and whole kharif season (June to October) as well as annually (January to December) to study the deficiency or surplus of water about its normal availability. In the same way, primary drought attributes, for example severity, frequency, magnitude, duration, intensity, return periods and trends, were computed and their distribution maps were prepared by employing geospatial techniques. During the study period, nearly half of the years experienced a meteorological drought at all-time scales. Fascinatingly, more than 90 percent of them were of mild drought, whereas severe and extreme droughts were unusual. Surprisingly, during the year 2002, all stations experienced a mixture of normal, moderate, severe and extreme droughts. The drought frequency followed an order of mid-season\u2009>\u2009whole kharif season\u2009>\u2009early season\u2009>\u2009late season\u2009>\u2009annual. The western, northern and southern parts (low to moderately elevated) experienced wetter conditions (significant at 95% confidence level). In contrast, the north eastern, eastern and south eastern regions (moderately to highly elevated) witnessed increased drier situations, though statistically it was found non-significant. Finally, the results of this study suggest that the investigation of SPI-based meteorological drought will be helpful in developing effective drought management plans over the dryland ecosystem.