Shanko, Dula (NMSA, Addis Ababa, Ethiopia)
The economy of Ethiopia depends mainly on rainfed Agriculture. The occurrence of drought imposes disastrous effects on the socio economic system in general and on the well being of the rural population in particular. The absence or deficiency of the moisture intrussion from the SWIO and the Arabian sea are very important for Ethiopia rainfall distribution depends on seasons.
The development of cyclonic features over the SWIO and the Arabian sea have an influence on Ethiopia rainfall.
This paper highlights the effect of tropical cyclones of the SWIO and the Arabian sea on Ethiopia drought. In order to study this effect the rainfall and the tropical cyclones data were subjected to statistical analysis. By using this approach, out of 42 rainfall stations 75.8% them were correlated negatively. About 85.70% & 71.4% of the grid points revealed that the seasonal occurrence of cyclones coincided with the drought years of Belg (February & May) and Kiremt (June to September) season respectively. Wet years of both Belg and Kiremt seasons have less frequency of tropical cyclones than drought years.
When the tropical cyclone named GERALDA took place in January 1994 over the SWIO, Ethiopia remained without any rainfall. During this time the synoptic systems occurred over the MEDITERRANEAN and adjacent areas brought dry air conditions over Ethiopia and resulted in across equatorial flow towards the weak pressure system of the southern hemisphere. The north and northeast equatorial flow enhances & Ethiopia regions remained free of cloud.
So that whenever there are sever and consecutive tropical cyclones over the SWIO there is a sucking of moisture towards its active center. Therefore the sequential occurrence of tropical cyclones on the SWIO in most cases coincided with the sever drought occurred in Ethiopia.