Variability and trends of climate in east Wollega zone, Western Ethiopia

Climate change is a major concern for the environmental, social and economic sectors of our world. The purpose of the study was to examine climate variability and trends in East Wollega Zone, Western Ethiopia. Daily precipitation and temperature information for 37 years (1981-2017) were gathered from the Ethiopian National Meteorological Agency. Mann-Kendall trend test, Sen Slope, linear regression model, and coefficient of variation were used to analyze data. The result found that monthly, seasonal and annual rainfall observed an insignificant declining trend except for May, November, and spring and the change was only significant for August at a significance level of 0.05. Maximum and minimum temperature revealed upward warming trends on a monthly, seasonal and yearly basis. The outcome of the linear regression model indicated an insignificant relationship between monthly, seasonal, and annual rainfall and time at a confidence level of 0.05. A statistically significant relationship has been detected between annual maximum, minimum, and mean temperature and year at 0.05 significance level. With the exception of winter minimum temperature, the result found a statistically significant relationship for seasonal temperature. The variation of seasonal rainfall was moderate for summer (23%) and autumn (29%) while it was high for spring (33%) and winter (65%) and it was also moderate for annual (23%). In view of the fact that crop production is affected by rainfall and temperature variability, adaptation to its adverse effect is imperative. Cropping system decisions and adaptation plans in the area should better accommodate for fluctuations in rainfall and temperature.