METEOROLOGICAL DROUGHT ANALYSIS BASED ON HISTORICAL RAIN FALL DAT A IN FIVE ZONES OF EASTERN AMHARA REGIONAL STATE

Abstract

Agricultural production in Ethiopia is predominantly rain fed. However, rain fall in the country is erratic and unreliable that can cause meteorological drought. Meteorological drought is a period of insufficient rainfall and quite often a natural hazard seriously damages agricultural production and water resources. The eastern five zones of Am hara region are part of this problem. The aim of this study is to understand the rainfall variation and conduct detail analysis of meteorological drought using drought characteristics index. This can provides reliable and detail information for planners and decision makers to address the current drought conditions in historical perspective. Standardized Precipitation Index (SPI) was selected to characterize drought condition in the study area. SPI require only rain fall as input data for its calculation of different time scales (2, 3, 6 and 12 months). It has a power to result five major drought characteristics duration, intensity, severity, magnitude and frequency. The analysis was made using data of on 34 rain gauge stations located inside the study area for the years1962 to 2007. The result obtained shows unreliable distribution and different amount of rain fall which caused different intensity of drought. The deficient rain water for 53-85% of the area with probability of 0.1-0.2 occurrence and 3-6 years spell for Kiremt in1982, 1984, and 1987 was affected by drought. During the Belg for more than 74% of the area were under drought with probability of 0.1 - 0.2 and spell of 3-10 years in 1984 and 1999. The year 1984 was severe drought year for both seasons for more than 82% of the area. In the analysis made Belg rain fall was highly sensitive and variable than Kiremt and other time scales for the whole years. The rainfall over the study area is highly variable with in the zone than between zones. The map of SPl-3K (Kiremt) and SPl-3B (Belg) show that a spatial extent of meteorological drought over the study area was irregular for the recent decades 1998 to 2007. This shows that the area is drought prone and vulnerable to meteorological drought which requires appropriate management measures.