ANALYSIS OF CLIMATE VARIABILITY AND THE ASSOCIATED METEOROLOGICAL DROUGHT IN THE SOUTHERN PART OF ETHIOPIAN RIFT VALLEY

Abstract

Nowadays, climate variability and its impact is the main concern put at the top of global agenda. Climate variability in Ethiopia where agriculture is the dominant sector of the economy is also increasingly attracting attention. A large percentage of the population is already vulnerable to a range of natural hazards with increasing climate variability and climate change expected to aggravate the situation further by causing more frequent and intense droughts. In this study, climate variability was assessed using different types of parameters such as coefficient of Variation(CV), rainfall anomaly index(RAI), Gaussian index(GI) and other variability causing agents such as onset date of rainfall in season and El- Nino seasonal impacts. The related meteorological drought occurrence in terms of severity, duration and frequency was also analyzed. The SPI calculator software was applied to compute drought in the study area. The study area practiced drought of different severity in different temporal and spatial scales other than common drought years that occurred throughout the area. In order to analyze future climate variability and related drought events, GCM derived scenarios (HadCM3 A2a & B2a SRES emission scenarios) were used for the climate projection. The future climatic elements such as rainfall, maximum temperature and minimum temperature are generated by SDSM software. There is high climate variability in the smaller rainy season and mostly moderate to high climate variability in the main rainy season. There will be low to moderate climate variability for both projection scenarios. The future climatic condition and the related drought were analyzed from the projected climate variables. There is a likely increasing maximum and minimum temperature for both HadCM3 A2a & B2a SRES emission scenarios. Precipitation also will increase in the study area with small decrease at Mirab station in2020s and slowly start to increase. Drought resulting from climate variability is likely to occur. Areas such as Mirab Abaya and Alaba station with smaller projected rainfall will be highly sensitive to dry climatic condition and the related drought. To reduce the impact of climate variability and the related drought, some measures such as high awareness on climate variability for food production, attention to early warnings and wise use of available water in the drought prone areas are recommended.