Climatic Variations, Trends and Drought Frequency in Dejen District, Nile Basin of Ethiopia

Temperature and rainfall variability affect systems such as water, agriculture, health, tourism, coastal areas, and biodiversity. This study examined climatic variability, and trends in Dejen district, Nile Basin of Ethiopia. The trends in temperature and rainfall over the period 1979-2014 were computed and tested for statistical significance. Results indicated a significant increase in temperature consistent with global temperature pattern. The decreasing trend in rainfall is contrary to the projections of a climate model for East Africa.The results show that the mean annual temperature increased by 1.66 ^OC. The maximum and minimum temperatures also rose by 2.16 ^OC and 1.91 ^OC respectively. The yearly rainfall declined by 399.96 millimeters. From 36 years of observation, 2002 and 2012 received below the average rainfall and characterized by arid years while 2008, 2011, 2013, 2014 years were moderately dry. The year 1983, 1986,1987,1996,1998, and 2010 were moderately wet. Among these negative patterns, the year 2002 and 2012 were extreme drought years. In the Nile Basin of Ethiopia, the variability and trends of temperature and rainfall, which hinders agricultural production are increasing and expected to increase in the future. This implies that the country specifically the study area whose mainstay depends on agriculture must cope with further warming, low, and erratic rainfall, and frequent climatic extremes.

Keywords
Climate change; drought frequency; standardized precipitation index; rainfall variations