Spatiotemporal variability and trends of drought episode in southeastern Ethiopia

ABSTRACT There is a need for scientific knowledge on the spatiotemporal variability of drought episodes to establish robust drought mitigation and adaptation strategies. This study evaluates the spatiotemporal variability of drought episodes in southeastern Ethiopia at multiple time scales (3-, 6-, 12- and 24-month and three spatially different wet seasons; March–May, June–September and September–November). Drought indices were generated for 34 stations using the standardized precipitation index (SPI). The results show that the frequency and magnitude of drought episodes do not have a clear spatial pattern among nearby stations. The 12- and 24-month SPI confirm that there has not been a year without drought (SPI≤ −1) between 1970 and 2015 at some stations in the study area. The trend tests show that drought magnitude, duration and geographical coverage are increasing. The increasing trends in drought magnitude at the annual, 24-month and during the March–May season were statistically significant at 0.05 level. Drought duration at 3-month time scale also showed a statistically significant increase. The results of this study provide relevant drought information at multiple time scales that is useful for supporting drought management in the southeastern Ethiopia.