Spatiotemporal variability and trends in extreme rainfall and temperature indices in Southeastern Oromia, Ethiopia

Abstract Extreme climatic events have become a significant global concern, exacerbating drought and flood risks in Ethiopia’s agricultural regions. This study presents the first multi-index analysis of 23 ETCCDI indices in southeastern Oromia (1994–2023) to address hydrological challenges. Using dat...

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Main Authors: Yared Tesfaye, Nigussie Dechassa, Yibekal Alemayehu, Dereje Ademe Birhan
Format: Article
Language:English
Published: Nature Portfolio 2025-08-01
Series:Scientific Reports
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Online Access:https://doi.org/10.1038/s41598-025-08411-6
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author Yared Tesfaye
Nigussie Dechassa
Yibekal Alemayehu
Dereje Ademe Birhan
author_facet Yared Tesfaye
Nigussie Dechassa
Yibekal Alemayehu
Dereje Ademe Birhan
author_sort Yared Tesfaye
collection DOAJ
description Abstract Extreme climatic events have become a significant global concern, exacerbating drought and flood risks in Ethiopia’s agricultural regions. This study presents the first multi-index analysis of 23 ETCCDI indices in southeastern Oromia (1994–2023) to address hydrological challenges. Using data from nine meteorological stations, we analyzed spatiotemporal trends via the Modified Mann-Kendall test with Hamed and Rao’s autocorrelation correction, Theil–Sen slope estimator, descriptive statistics, linear regression, and Standardized Anomaly Index (SAI). Spatial interpolation employed Inverse Distance Weighting (IDW). The results show that the rainfall extremes (CWD, R20mm, R25mm) and temperature indices (TNn, SU25, CSDI, WSDI) exhibited high variability (CV > 30%). Significant declines occurred in RX1day, R95p, and R99p, while CDD increased by + 0.4 to + 1.17 days/year at 77.8% of stations. Warming trends dominated: TX90p and TN90p rose by 0.10 to 0.57 and 0.20 to 0.60 days/year, respectively; TXx and TNx increased by 0.03 to 0.2 °C/year and 0.05 to 0.12 °C/year at all stations. All stations showed rising TXx, TNx, TX90p, and TN90p, with 66.7% recording more SU days. Hot indices (TXx, TNx, TX90p, TN90p, SU) increased as cold indices (TNn, TXn, TX10p, TN10p) declined, highlighting warming asymmetry. Spatial analysis revealed station-specific variability, emphasizing localized climate risks. These trends demand urgent adaptive strategies to mitigate escalating climate threats in vulnerable regions.
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spelling doaj-art-e0ab0cc94be647eabd2c5cd2e8347e5a2025-08-20T03:05:21ZengNature PortfolioScientific Reports2045-23222025-08-0115113010.1038/s41598-025-08411-6Spatiotemporal variability and trends in extreme rainfall and temperature indices in Southeastern Oromia, EthiopiaYared Tesfaye0Nigussie Dechassa1Yibekal Alemayehu2Dereje Ademe Birhan3Haramaya University College of Agricultural and Environmental SciencesEthiopian Institute of Agricultural ResearchCollege of Agriculture, School of Plant Sciences, Haramaya UniversityDepartment of Soil and Water Science, Institute of Food and Agricultural Sciences, University of FloridaAbstract Extreme climatic events have become a significant global concern, exacerbating drought and flood risks in Ethiopia’s agricultural regions. This study presents the first multi-index analysis of 23 ETCCDI indices in southeastern Oromia (1994–2023) to address hydrological challenges. Using data from nine meteorological stations, we analyzed spatiotemporal trends via the Modified Mann-Kendall test with Hamed and Rao’s autocorrelation correction, Theil–Sen slope estimator, descriptive statistics, linear regression, and Standardized Anomaly Index (SAI). Spatial interpolation employed Inverse Distance Weighting (IDW). The results show that the rainfall extremes (CWD, R20mm, R25mm) and temperature indices (TNn, SU25, CSDI, WSDI) exhibited high variability (CV > 30%). Significant declines occurred in RX1day, R95p, and R99p, while CDD increased by + 0.4 to + 1.17 days/year at 77.8% of stations. Warming trends dominated: TX90p and TN90p rose by 0.10 to 0.57 and 0.20 to 0.60 days/year, respectively; TXx and TNx increased by 0.03 to 0.2 °C/year and 0.05 to 0.12 °C/year at all stations. All stations showed rising TXx, TNx, TX90p, and TN90p, with 66.7% recording more SU days. Hot indices (TXx, TNx, TX90p, TN90p, SU) increased as cold indices (TNn, TXn, TX10p, TN10p) declined, highlighting warming asymmetry. Spatial analysis revealed station-specific variability, emphasizing localized climate risks. These trends demand urgent adaptive strategies to mitigate escalating climate threats in vulnerable regions.https://doi.org/10.1038/s41598-025-08411-6Climate changeExtreme indicesMK trend testIDW
spellingShingle Yared Tesfaye
Nigussie Dechassa
Yibekal Alemayehu
Dereje Ademe Birhan
Spatiotemporal variability and trends in extreme rainfall and temperature indices in Southeastern Oromia, Ethiopia
Scientific Reports
Climate change
Extreme indices
MK trend test
IDW
title Spatiotemporal variability and trends in extreme rainfall and temperature indices in Southeastern Oromia, Ethiopia
title_full Spatiotemporal variability and trends in extreme rainfall and temperature indices in Southeastern Oromia, Ethiopia
title_fullStr Spatiotemporal variability and trends in extreme rainfall and temperature indices in Southeastern Oromia, Ethiopia
title_full_unstemmed Spatiotemporal variability and trends in extreme rainfall and temperature indices in Southeastern Oromia, Ethiopia
title_short Spatiotemporal variability and trends in extreme rainfall and temperature indices in Southeastern Oromia, Ethiopia
title_sort spatiotemporal variability and trends in extreme rainfall and temperature indices in southeastern oromia ethiopia
topic Climate change
Extreme indices
MK trend test
IDW
url https://doi.org/10.1038/s41598-025-08411-6
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