Centre for Environmental Science, College of Natural and Computational Science, Ababa University, Addis, Ethiopia.
Department of Ecobiology, College of Applied Sciences, Addis Ababa Science and Technology University, Addis, Ethiopia.
ScientificWorldJournal. 2022 Feb 14;2022:1181198. doi: 10.1155/2022/1181198. eCollection 2022.
In Ethiopia, more prevalent drought happenings have been documented in the past century. The problem has gradually expanded from the north to the rest parts with deepened intensity. The study aimed to examine the magnitudes of spatiotemporal patterns of drought at the Bilate watershed from 1981 to 2016. Monthly rainfall and temperature data were used for the analysis. The Standardized Evapotranspiration Indexes (SPEI) at SPEI-03 and SPEI-12 timescales were applied to evaluate the drought patterns. Among different drought indices, the SPEI is the most valuable and preferred Index for drought studies. The SPEI method considers the role of temperature than other indices to compare drought in time and space. The Mann-Kendall test was used for trend analysis. Accordingly, the result revealed that 1988-2016 were years of continuous drought events in both timescales with (SPEI = -2.5 to -1.2) drought value. Drought severity and frequency were highly detected at Wulberag areas (SPEI: -2.5). Durame, Angacha, and Alaba experienced increasing drought trends ( = -1.96-1.6) and Welayita Sodo is = -0.07-0.03. Bilate-Tena and Hossana area of the watershed were less affected by drought than other areas. Spatially, the drought occurrences were observed in all areas of the watershed with varying magnitude. In the SPEI-12 timescale, more frequent drought occurrences were observed than SPEI-03. It was found that severe drought was observed in 1987, 1993/94, 2000-2005, and 2010. Moreover, the watershed experienced an Aridity Index (AI) of 0.43 (43%) and was subjected to potential high evapotranspiration (PET). The highest PET was observed at Bilate-Tena, Angacha, Hosanna, Wulberag, Alaba, Welayita Sodo, and Durame (151.6, 119.6, 119.3, 140.8, 142, 127.5, and 125.7 mm/year, respectively. Hence, the finding of this study could initiate a further inquiry on drought risk management, early warning responses, and local scale planning.
在埃塞俄比亚，过去一个世纪记录了更多普遍的干旱事件。这个问题已经逐渐从北部扩展到其他地区，强度也在加深。本研究旨在检验 1981 年至 2016 年比莱特流域干旱时空格局的幅度。使用月降雨量和温度数据进行分析。应用标准蒸发蒸腾指数（SPEI）在 SPEI-03 和 SPEI-12 时间尺度上评估干旱模式。在不同的干旱指数中，SPEI 是最有价值和首选的干旱研究指数。SPEI 方法考虑了温度的作用，而不是其他指数来比较时间和空间上的干旱。Mann-Kendall 检验用于趋势分析。结果表明，在两个时间尺度上，1988-2016 年都是连续干旱事件年（SPEI=-2.5 至-1.2）干旱值。在 Wulberag 地区（SPEI=-2.5）高度检测到干旱严重程度和频率。Durame、Angacha 和 Alaba 经历了干旱趋势的增加（=−1.96-1.6），而 Welayita Sodo 则为=−0.07-0.03。比莱特-特纳和霍萨纳流域地区受干旱影响小于其他地区。空间上，流域所有地区都发生了不同程度的干旱。在 SPEI-12 时间尺度上，观测到的干旱发生频率高于 SPEI-03。结果表明，1987 年、1993/94 年、2000-2005 年和 2010 年发生了严重干旱。此外，流域的干旱指数（AI）为 0.43（43%），可能面临高蒸散量（PET）。在比莱特-特纳、安加查、霍萨纳、Wulberag、Alaba、Welayita Sodo 和 Durame 观测到的最高 PET 分别为 151.6、119.6、119.3、140.8、142、127.5 和 125.7mm/年。因此，本研究的结果可以进一步探讨干旱风险管理、早期预警响应和地方尺度规划。
