The temporal distribution of Ethiopian meteorological droughts in the 20 century
1993
Seleshi, Y. | Demaree, G. (Institut Royal Meteorologique de Belgique, Bruxelles (Belgium))
During the 20th century, Ethiopia has experienced several periods of dry conditions (droughts) of varying magnitude, duration and spatial extent. As a result, several highly populated areas in the drought prone regions of Ethiopia have been seriously affected and this, in some cases, resulted in widespread famine. Hence, the study of drought characteristics is of tremendous importance. Meteorological drought is defined in terms of deficit from a given bottom threshold (e.g. 80 per cent of the long-term avarage of the June-September rainfall amounts). June-September rainfall amounts at Addis Ababa and Asmara, which account for 72 per cent and 78 per cent of annual precipitation amounts respectively, are considered. Based on the above meteorological drought definition, the number of meteorological drought years in the period 1903-1990 at Asmara is found to be 29 while at Addis Ababa it is only 14. The approximate mean recurrence interval of the meteorological drought is estimated to be 6.3 years at Addis Ababa and 3.0 years at Asmara. In the present work the temporal and geographical changes in frequency of meteorological droughts for consecutive 21-year, 11-year and 5-year periods are successively discussed. It is found that the period with the highest temporal concentration of meteorological drought frequency at Asmara is from the mid-60s to the mid-70s, while at Addis Ababa it is during the 50s. Some links between drought desertification in the region are also given
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