Meteorological Drought Assessment using GeoCLIM: Case Study East and West Hararghe, Oromia, Ethiopia

Drought is a hazardous and costly natural phenomenon with slow on-set that has dreadful impacts on economy, social life and environment of a country or region. The fact that it is slow on-set and is not quite distinguishable in when is it started or when ended makes the phenomena difficult to study (Hammouri and Naqa, 2007). Drought appears when rainfall in a region is less than statistical multiyear average for that region over an extended time period (Malaet al., 2014). It is a normal climatic event but its effect varies from region to region. There are four types of drought namely; meteorological drought, agricultural drought, hydrological drought and socio economic drought (Rathore, 2009). Meteorological drought is deficiency of rainfall which can be observed immediately (Panu andSharma, 2002). Although drought is a natural occurring recurrent extreme event (Wilhite, 1993; Shatanawi et al., 2013), various empirical and modelling studies proved that climate change is very likely to increase the magnitude, frequency and duration of droughts over some parts of the world in the coming decades (IPCC II, 2014, Degefu and Bewket, 2013). In recent years, Geographical Information System (GIS) and GeoCLIM Tool have played a key role in studying different types if hazards either natural or man-made. This study stresses upon the use of GeoCLIM Tool in the field of Drought Risk assessment. In this study an effort has been made to derive spatial temporal drought risk areas facing as meteorological drought by GeoCLIM Tool and meteorological based Standardized Precipitation Index (SPI). Analysis was performed on CV, SPI, and average rainfall anomaly. SPI values were interpolated to get the spatial pattern of meteorological based drought. In the study period 25% was Very severe drought year while 75% were slight to severe drought categories. It was evident from the study that western and east tip of the study region were exposed to high frequency of severe and very severe droughts at annual time scale. Very severe droughts were more pronounced in areas where their altitude is above 1,520m3,275m masl. Increasing tendencies of drought were observed during recent year. The results obtained can be helpful for drought management plans and will help in revealing true drought situation in the area.