Analysis of Precipitation and Temperature Trends Under the Impact of Climate Change Over Ten Districts of Jimma Zone, Ethiopia

摘要

This study aimed to investigates the precipitation and temperature trends over ten districts of Jimma zone in the twenty-first century using observed and model simulation data sets. The precipitation and temperature trends are analyzed for the reference (1981-2010) and two future periods, namely, mid-century (2031-2060), and end-century (2071-2100) using Innovative Trend Analysis. For future period, we analyzed the ensemble mean of precipitation and temperature based on data from four high resolution models, namely, High-Resolution Hamburg Climate Model 5, Regional Atmospheric Climate Model (RACMO22T), Climate Limited-Area Modeling Community (CCLM4), and the Rossby Centre Regional Atmospheric Model (RCA4). Based on the analysis, the annual, summer and autumn rainfall trend during the reference period are - 4.079 mm/year, 2.147 mm/year, and - 1.639 mm/year, respectively. The winter rainfall reveals a negative trend (- 0.135 mm/year) during the reference period. However, the winter rainfall shows a positive trend (0.465 mm/year and 0.067 mm/year) towards the end-century period under RCP4.5 and RCP8.5 scenarios. On the contrary, the autumn rainfall showed consistent decreasing trend during the two future periods. The maximum increasing trend (1.376 mm/year) in annual rainfall was obtained during the mid-century period under RCP4.5 scenario, whereas the maximum annual decreasing rainfall trend was obtained during the mid-century period under RCP8.5 scenario (- 0.649 mm/year). The minimum temperature showed significant increasing trend throughout the study periods. However, the maximum temperature showed decreasing trend during annual and winter in the mid-century period under RCP4.5 and RCP8.5 scenarios. The highest increasing trend of the minimum temperature was during winter and autumn, while the highest increasing trend of the maximum temperature was during the summer and autumn seasons. The result further indicate that the minimum temperature increment was faster as compared to the maximum temperature. The study can be used as a first-hand information to develop efficient adaptation policies and mitigation measures that aids to combat the adverse impact of climate change.