Climate change raises important issues concerning hydrological engineering. The impact of climate change on important river basins should be investigated rigorously. Extreme temperature variability has a direct impact on the hydrological cycle, especially the evaporation component. In this paper, spatial and temporal patterns of changes in extreme temperatures were investigated using 10 meteorological stations' data for the period 1950–2018 in the Blue Nile Basin. Long-term trends in the Blue Nile Basin annual and monthly temperatures were investigated. The statistical significance of the trend was calculated by applying the Mann–Kendall (MK) test. The analysis of data was performed using the coefficient of variance and anomaly index. The results showed that the annual maximum and minimum temperatures were increasing significantly with a magnitude of 0.037 and 0.025 ^∘C per decade respectively in the period from 1950 to 2018. The result of the Mann–Kendall analysis test revealed a marked increase in the mean maximum and minimum temperature trends over time during the study period (the minimum temperature rate is more evident than the maximum). The long-term anomalies of mean annual minimum temperature revealed the interannual variability while the trend after 1977 was higher than the long-term average, which is proof of the warming trend's existence during the last two decades of the 20th century.

中文翻译：

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评估埃塞俄比亚青尼罗河流域气候变化对极端温度变化的影响

气候变化提出了有关水文工程的重要问题。应严格研究气候变化对重要流域的影响。极端的温度变化直接影响水文循环，尤其是蒸发分量。在本文中，我们使用Blue Nile盆地1950-2018年期间10个气象站的数据，研究了极端温度变化的时空格局。研究了青尼罗河盆地年度和每月温度的长期趋势。通过应用Mann-Kendall（MK）检验计算出趋势的统计显着性。使用方差系数和异常指数进行数据分析。 在1950年至2018年期间，每十年每^{度∘C。Mann} –Kendall分析测试的结果显示，在研究期间，平均最高和最低温度趋势随时间显着增加（最低温度速率比最大限度）。年平均最低温度的长期异常揭示了年际变化，而1977年以后的趋势高于长期平均，这证明了在20世纪最后二十年中存在变暖趋势。