Abstract
Climate change has become a challenge for the globe and impacting various systems. This study evaluated the seasonal and annual variabilities and trends of rainfall, temperature, and potential evapotranspiration for the period 1985–2019 over Bilate basin of Rift Valley Lakes basins in Ethiopia. Twenty rain and eleven temperature gauge stations datasets were used. Coefficient of variation and precipitation concentration indices were used for variability analysis, whereas Mann–Kendall test and Sen’s slope estimator were used for trend detection and magnitude. The short and main rainy seasons characterized the basin with a bimodal rainfall pattern. Variability indices revealed dry Bega season with significant rainfall variability. In the dry season, higher relative variability is exhibited in the upstream north and lesser in the downstream south which flips in the main rainy season. Internal climate variability evaluation with indices showed a weak correlation with the observed rainfall variabilities for seasons. Inter-annual and seasonal anomalies characterize inconsistent wet and dry years, which uncertainly impact climate-sensitive rainfed agriculture. The areal weighted average rainfall shows negligible declining trend (α = 0.05) with a magnitude of 2.45 mm/year and 2.60 mm/year for annual and Belg, respectively. The minimum average temperature was relatively more variable than the maximum average temperature. Most of the stations established warming trends either negligible or significant. Potential evapotranspiration exhibited less variability with negligible trends in the majority of the stations. Therefore, rainfed agricultural practices and water resources use in the basin should adapt with supplementing measures to respond to uncertain variabilities and minor changes.
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Acknowledgements
We thank Ethiopian National Meteorological Agency for supplying meteorological data for free. We also thank the seven anonymous reviewers for their insightful comments to earlier drafts of this manuscript.
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Conceived and designed the idea [Biruk TL]; material preparation, data collection, and analysis [Biruk TL]; the first draft of the manuscript [Biruk TL]; supervision [Subrahmanya K]. All authors read and approved the final manuscript.
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Lambe, B.T., Kundapura, S. Analysis of meteorological variability and tendency over Bilate basin of Rift Valley Lakes basins in Ethiopia. Arab J Geosci 14, 2692 (2021). https://doi.org/10.1007/s12517-021-08962-8
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DOI: https://doi.org/10.1007/s12517-021-08962-8