A new early warning drought index for Ethiopia

This study investigates the occurrence of droughts in the Dire Dawa area of eastern Ethiopia. A new index based on the rainfall delay (Rd) with respect to the expected onset (and traditional) seeding time and other indices, i.e., the aridity index and the Z-score, alternatives to the Standard Precipitation Index (SPI), are used to test the validity of the new Rd index in identifying severe droughts extending back to 1955. Although only data of rain gauges located in the district of Dire Dawa were used, they proved, albeit with different accuracies, able to identify nation-wide droughts.