Deressa Tolamariam Chimdessa, Chalchissa Fedhasa Benti, Gemeda Dessalegn Obsi
Department of Natural Resources Management, College of Agriculture and Veterinary Medicine, Jimma University, Jimma, Ethiopia.
Center for Energy and Environmental Research, Wallaga University, Nekemte, Ethiopia.
Environ Monit Assess. 2025 Jun 17;197(7):759. doi: 10.1007/s10661-025-14195-z.
Climate change significantly impacts countries that rely on rainfed agriculture. This study examined the patterns and trends of temperature and precipitation, rainfall onset, rainy season dry spells, rainfall cessation, and length of the growing season in Horro Guduru Wallaga Zone. Gridded daily rainfall, minimum temperature and maximum temperature data (1981-2020) were collected from seven stations operated by the Ethiopian Meteorological Institute (EMI). Climate variability was assessed using the coefficient of variation, precipitation concentration index, and standardized rainfall anomaly. The trend and their magnitude were determined using the Mann‒Kendall test and Sen's slope estimator, respectively. Results show that the spring and winter seasons exhibited high variability while autumn displayed moderate variability. There is an overall increase in annual rainfall with statistically significant trends at three out of seven stations. Autumn, summer, and spring seasons showed increasing trends whereas winter exhibited a downward trend. Moreover, 71% and 86% of the stations experienced a significant upward trend in mean annual minimum and maximum temperatures, respectively. Overall, both minimum and maximum temperatures are experiencing upward trends, with significant variations in rainfall patterns across different seasons. The distribution of rainfall was predominantly irregular with extreme and severe droughts occurring in 1984, 1986, and 2015. Earlier onset dates and later cessation dates were also detected in this study. These irregularities can lead to land degradation, which results to yield loss appropriate climate change adaptation measures.
气候变化对依赖雨养农业的国家产生重大影响。本研究考察了霍罗古杜鲁瓦拉加地区的气温和降水模式及趋势、降雨开始时间、雨季干旱期、降雨结束时间和生长季长度。从埃塞俄比亚气象研究所（EMI）运营的7个站点收集了网格化的日降雨量、最低气温和最高气温数据（1981 - 2020年）。使用变异系数、降水集中度指数和标准化降雨异常评估气候变异性。分别使用曼 - 肯德尔检验和森斜率估计器确定趋势及其幅度。结果表明，春季和冬季变异性高，而秋季变异性中等。年降雨量总体增加，7个站点中有3个站点呈现出具有统计学意义的趋势。秋季、夏季和春季呈上升趋势，而冬季呈下降趋势。此外，71%和86%的站点年均最低气温和最高气温分别呈显著上升趋势。总体而言，最低气温和最高气温均呈上升趋势，不同季节的降雨模式存在显著差异。降雨分布主要不规则，1984年、1986年和2015年出现了极端和严重干旱。本研究还检测到降雨开始日期提前和结束日期推迟。这些不规则情况可能导致土地退化，进而导致产量损失，因此需要采取适当的气候变化适应措施。
