Abstract
This study investigated the space-time drought incidence in the northeastern highlands of Ethiopia using monthly rainfall data. It also aims to predict drought events for 100 years. The Standardized Precipitation Index (SPI) was used to compute the drought severity classes of rainy months and seasons at 1-, 4- and 8-months timesteps. The Mann-Kendall’s test and Sen’s slope estimator were used to analyze the trends of drought events and to determine the magnitude of change. Inverse Distance Weighted spatial analysis tool was used to illustrate the spatial patterns of the drought risk events. The study detected extreme severe droughts in the belg rainy months in March 2008 and April 1984. However, during the belg season, the year 1999 was the driest for the recorded periods. On the other hand, the extremely severe droughts were observed during the kiremt rainy months of July 1987 and 2015, August 1984, and September 2009. In general, 1984, 1987 and 2015 were the driest years recorded in the kiremt season. The study noted that the drought risk events of months in the belg season were threefold greater than that of the months in kiremt season under moderate drought intensity class. Equally, the drought risk events of months in kiremt season were threefold greater than that of the belg season under extreme drought intensity class. Complex spatial variations of drought risk events were also observed in 1-, 4- and 8-months timesteps. During the belg seasons, the southern half was subjected to more frequent drought risk events while the northern half experienced more frequent drought risk events during kiremt season. Almost the eastern half of the livelihood zones experienced higher drought frequency events than the other parts in the 8-month timestep. The observed space-time drought risk event analysis has shown a potential threat to the rainfed agricultural practices that have a great influence on the livelihoods of smallholder farmers. Hence, documentation and assessment of drought risk events based on the livelihood zones are essential for drought risk management, early warning responses, local-scale planning and food security management. Finally, the study recommended further research on additional indices of climatic variables such as evapotranspiration and soil water content.
Highlights
Drought is a commonly used term, but the most complex and least realized of all the natural hazards affecting more people than any other hazards (Wilhite 2000; Ashraf and Routray 2013)
The drought magnitudes of the small rainy months were ranged from − 9.45 in March to − 11.83 in May
The extreme severe droughts were observed in March 2008 and April 1984 with the severity of peak Standardized Precipitation Index (SPI)-values of − 2.49 and − 2.23, respectively
Summary
Drought is a commonly used term, but the most complex and least realized of all the natural hazards affecting more people than any other hazards (Wilhite 2000; Ashraf and Routray 2013). Since drought is a recurrent climatic phenomenon, its outcome is manifested through immense damage to agriculture production, reduction of water supply and energy production, mass migration and loss of life (Masih et al 2014). Writers such as –Sheffield and Wood (2007), Bannayan et al (2010), and Degefu and Bewket (2015) differently showed that the causes and influences of drought in space-time on the environment are determined by the attributes of frequency, magnitude, intensity, and spatial extent. Within the period 1960–2016, there were about 669 drought events reported across the world, and it has killed about 2.2 million people and affected over 2.6 billion people and an estimated economic damage of 146 billion US Dolar Centre for Research on the Epidemiology of Disasters/CRED (2016)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
