This study investigated the intensity, trend and spatio-temporal variability of meteorological drought in the Lakes’ Region of Ethiopian Rift Valley using monthly rainfall and maximum and minimum temperature records for the period 1986–2019. Reconnaissance Drought Index (RDI) was employed to generate the intensity of drought at 3 and 12-months timescale. Mann-Kendall trend test was used to determine the trend of the changes in the RDI time series. The spatial extent of droughts has been interpolated by inverse distance weighted (IDW) method using the spatial analyst tool of ArcGIS. Results indicated the occurrence of different intensity and trend signals across seasons and over space in the study area. A total of 33 extreme drought months were observed in all stations during summer with varying intensity (− 2.01 at Halaba to − 3.52 at Wolaita) and 168 extreme drought months at annual timescale ranging from − 2.10 at Hawassa to − 4.51 at Wolaita. The intensity of drought events observed in Wolaita in 1986 at all timescales (RDI value of − 3.19, − 3.52 and − 4.51 for spring, summer and annual respectively) were very extraordinary and devastating. Drought magnitude showed increasing signal at 6 out of 10 stations, although statistically significant at only two stations (Arsi Negelle at all timescale and Butajira at spring and annual timescale). However, the spatial patterns of drought events didn’t exhibit clear pattern rather more localized distribution and variability. The frequency of drought incidence became intense in the study area from 2008 onwards at all timescales compared to the 1990s and 2000s.The increasing tendency of drought in recent years might be the manifestation of borderless global warming. The empirical evidences showed that drought events and their negative effects are highly localized in the study area and provide useful information for local-scale planning for drought management and response.

中文翻译：

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使用侦察干旱指数 (RDI) 分析埃塞俄比亚裂谷湖区的气象干旱

本研究利用 1986 年至 2019 年期间的月降雨量和最高和最低温度记录，调查了埃塞俄比亚裂谷湖区气象干旱的强度、趋势和时空变化。使用侦察干旱指数 (RDI) 来生成 3 个月和 12 个月时间尺度的干旱强度。Mann-Kendall 趋势检验用于确定 RDI 时间序列的变化趋势。干旱的空间范围已使用ArcGIS 的空间分析工具通过反距离加权（IDW）方法进行插值。结果表明，研究区跨季节和跨空间出现不同强度和趋势信号。在夏季，所有站点共观察到 33 个极端干旱月份，强度不同（哈拉巴的 - 2.01 至 - 3。52 在 Wolaita）和 168 个极端干旱月，在年度时间尺度上从 - 2.10 在 Hawassa 到 - 4.51 在 Wolaita。1986 年在沃莱塔观测到的所有时间尺度的干旱事件强度（春季、夏季和年度的 RDI 值分别为 − 3.19、− 3.52 和 − 4.51）都非常非同寻常且具有破坏性。干旱幅度在 10 个站点中的 6 个站点显示出增加的信号，尽管只有两个站点（所有时间尺度的 Arsi Negelle 和春季和年度时间尺度的 Butajira）具有统计显着性。然而，干旱事件的空间格局并没有表现出明显的格局，而是更加局部的分布和变异。与 1990 年代和 2000 年代相比，研究区从 2008 年起在所有时间尺度上的干旱发生频率都变得很高。近年来干旱的加剧趋势可能是全球变暖无国界的表现。经验证据表明，干旱事件及其负面影响在研究区域高度局部化，为当地规模的干旱管理和响应规划提供了有用的信息。