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<front>
<journal-meta>
<journal-id journal-id-type="publisher">EGUsphere</journal-id>
<journal-title-group>
<journal-title>EGUsphere</journal-title>
<abbrev-journal-title abbrev-type="publisher">EGUsphere</abbrev-journal-title>
<abbrev-journal-title abbrev-type="nlm-ta">EGUsphere</abbrev-journal-title>
</journal-title-group>
<issn pub-type="epub"></issn>
<publisher><publisher-name>Copernicus Publications</publisher-name>
<publisher-loc>Göttingen, Germany</publisher-loc>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.5194/egusphere-2026-1969</article-id>
<title-group>
<article-title>Accelerated Hydrological Wet-to-Dry Transitions and Their Driving Mechanisms over Africa</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Gurara</surname>
<given-names>Megersa Adugna</given-names>
<ext-link>https://orcid.org/0000-0003-2318-8109</ext-link>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
<xref ref-type="aff" rid="aff4">
<sup>4</sup>
</xref>
<xref ref-type="aff" rid="aff5">
<sup>5</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Zhao</surname>
<given-names>Gang</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
<xref ref-type="aff" rid="aff4">
<sup>4</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Liu</surname>
<given-names>Xingcai</given-names>
<ext-link>https://orcid.org/0000-0001-5726-7353</ext-link>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Xu</surname>
<given-names>Ximeng</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Gaffney</surname>
<given-names>Paul P. J.</given-names>
</name>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Tang</surname>
<given-names>Qiuhong</given-names>
<ext-link>https://orcid.org/0000-0002-0886-6699</ext-link>
</name>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences  and Natural Resources Research, CAS, Beijing, China</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>Key Laboratory of Groundwater Conservation of the Ministry of Water Resources, China University of  Geosciences, Beijing 100083, China</addr-line>
</aff>
<aff id="aff3">
<label>3</label>
<addr-line>Department of Earth System Science, Tsinghua University, Beijing, China</addr-line>
</aff>
<aff id="aff4">
<label>4</label>
<addr-line>University of Chinese Academy of Sciences, Beijing, China</addr-line>
</aff>
<aff id="aff5">
<label>5</label>
<addr-line>Department of Water Resource and Irrigation Engineering, Haramaya Institute of Technology,  Haramaya University, Ethiopia</addr-line>
</aff>
<pub-date pub-type="epub">
<day>27</day>
<month>04</month>
<year>2026</year>
</pub-date>
<volume>2026</volume>
<fpage>1</fpage>
<lpage>33</lpage>
<permissions>
<copyright-statement>Copyright: &#x000a9; 2026 Megersa Adugna Gurara et al.</copyright-statement>
<copyright-year>2026</copyright-year>
<license license-type="open-access">
<license-p>This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit <ext-link ext-link-type="uri"  xlink:href="https://creativecommons.org/licenses/by/4.0/">https://creativecommons.org/licenses/by/4.0/</ext-link></license-p>
</license>
</permissions>
<self-uri xlink:href="https://egusphere.copernicus.org/preprints/2026/egusphere-2026-1969/">This article is available from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-1969/</self-uri>
<self-uri xlink:href="https://egusphere.copernicus.org/preprints/2026/egusphere-2026-1969/egusphere-2026-1969.pdf">The full text article is available as a PDF file from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-1969/egusphere-2026-1969.pdf</self-uri>
<abstract>
<p>Abrupt wet-to-dry (W2D) events represent a damaging natural disaster, exerting more far-reaching impacts on the environment and society than single extreme events. While sub-seasonal and interannual precipitation whiplash have recently been analyzed, hydrological W2D transitions, especially at smaller time scales such as sub-monthly, have yet to be examined. In this study, we quantify changes in the characteristics of hydrological W2D transitions based on soil moisture in Africa and identify the drivers behind these changes. The results show that the total W2D transition has accelerated markedly: transition speed increased by 19 % and duration shortened by 10 % from 1981 to 2024. The area averaged proportion of rapid W2D events to total W2D events has increased from 52 % during 1981&amp;ndash;2000 to 58 % during 2001&amp;ndash;2024. The spatial extent of rapid W2D transitions has increased significantly. On average, 13 % of the continent has experienced rapid W2D transition in the 1980s, increasing to 17 % after 2010. These findings suggest a general shift from slow to rapid hydrological W2D transitions on a sub-monthly timescale. We further find that the speeding up of W2D transition onset is driven by greater precipitation deficits, higher temperature, and higher evaporative demand during the transition onset period. Overall, the shift from slow to rapid W2D transitions reduces the predictability of hydrological volatility regimes, which has adverse impacts on agriculture, ecological stability, and water resources management.</p>
</abstract>
<counts><page-count count="33"/></counts>
<funding-group>
<award-group id="gs1">
<funding-source>National Natural Science Foundation of China</funding-source>
<award-id>U2243226</award-id>
</award-group>
</funding-group>
</article-meta>
</front>
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