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<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-2026-5194</article-id>
<title-group>
<article-title>Multifractal characterization of daily maximum and minimum ionospheric TEC at African equatorial stations</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Rabiu</surname>
<given-names>Babatunde</given-names>
<ext-link>https://orcid.org/0000-0002-2734-5389</ext-link>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Ogunjo</surname>
<given-names>Samuel</given-names>
<ext-link>https://orcid.org/0000-0002-6986-1939</ext-link>
</name>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Olabode</surname>
<given-names>Ayomide</given-names>
</name>
<xref ref-type="aff" rid="aff4">
<sup>4</sup>
</xref>
<xref ref-type="aff" rid="aff5">
<sup>5</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Institute of Space Science and Engineering, African University of Science and Technology, 900107 Abuja, Nigeria</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>Network of Space-Earth Environmentalists, 900107 Abuja, Nigeria</addr-line>
</aff>
<aff id="aff3">
<label>3</label>
<addr-line>Department of Physics, Federal University of Technology Akure, 340252 Akure, Nigeria</addr-line>
</aff>
<aff id="aff4">
<label>4</label>
<addr-line>Institut fur Geodesie und Geoinfomationstechnik, Technische Universitat Berlin, 10553 Berlin, Germany</addr-line>
</aff>
<aff id="aff5">
<label>5</label>
<addr-line>Department of Physics and Engineering Physics, Obafemi Awolowo University, 220282 Ile-Ife, Nigeria</addr-line>
</aff>
<pub-date pub-type="epub">
<day>04</day>
<month>09</month>
<year>2026</year>
</pub-date>
<volume>2026</volume>
<fpage>1</fpage>
<lpage>19</lpage>
<permissions>
<copyright-statement>Copyright: &#x000a9; 2026 Babatunde Rabiu 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-2026-5194/">This article is available from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-5194/</self-uri>
<self-uri xlink:href="https://egusphere.copernicus.org/preprints/2026/egusphere-2026-5194/egusphere-2026-5194.pdf">The full text article is available as a PDF file from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-5194/egusphere-2026-5194.pdf</self-uri>
<abstract>
<p>The temporal scaling structure of the ionospheric vertical total electron content (vTEC) carries fundamental information about the intrinsic dynamics of the equatorial and low-latitude plasma system. This study applies Multifractal Detrended Fluctuation Analysis (MFDFA) to investigate the intrinsic dynamics of the variability of the ionosphere over African equatorial stations using the daily maximum and minimum vTEC time series recorded at three GNSS stations (Dakar (DAKR), Libreville (NKLG), and Djibouti (DJIG) spanning the equatorial ionisation anomaly (EIA) crest and its flanks. Seasonal trend components are isolated using Seasonal and Trend decomposition with Loess (STL) to separate the contribution of the seasonal cycle from intrinsic ionospheric dynamics. The raw maximum vTEC series exhibit clear semi-annual modulation and multifractality at all stations, with generalised Hurst exponents 0.104 &amp;le;&lt;span&gt;&amp;thinsp;&lt;/span&gt;&lt;em&gt;h&lt;span&gt;&amp;thinsp;&lt;/span&gt;&lt;/em&gt;(&lt;em&gt;q&lt;span&gt;&amp;thinsp;&lt;/span&gt;&lt;/em&gt;=&lt;span&gt;&amp;thinsp;&lt;/span&gt;2)&lt;span&gt;&amp;thinsp;&lt;/span&gt;&amp;le;&lt;span&gt;&amp;thinsp;&lt;/span&gt;0.193 and statistically significant singularity spectral widths. A crossover in scaling behaviour near &lt;em&gt;n&lt;span&gt;&amp;thinsp;&lt;/span&gt;&lt;/em&gt;&amp;asymp;&lt;span&gt;&amp;thinsp;&lt;/span&gt;150 days reveals scale-dependent persistence that is stronger at sub-annual scales. The raw minimum vTEC series confirm multifractality but with consistently narrower singularity spectra and weaker &lt;em&gt;q&lt;/em&gt;-dependence, reflecting the reduced dynamic range of the nighttime ionosphere in the absence of photo-ionisation. These results reveal a clear daytime-nighttime asymmetry in ionospheric scaling dynamics and establish the EIA crest as a region of persistent, non-seasonal nonlinear variability that manifests across both the daytime and nighttime ionosphere. The findings demonstrate that MFDFA applied to the diurnal extremes of vTEC provides a sensitive and physically interpretable diagnostic of equatorial ionospheric complexity that is not accessible through conventional spectral or trend-based analyses.</p>
</abstract>
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