<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE article PUBLIC "-//NLM//DTD Journal Publishing DTD v3.0 20080202//EN" "https://jats.nlm.nih.gov/nlm-dtd/publishing/3.0/journalpublishing3.dtd">
<article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" article-type="research-article" specific-use="SMUR" dtd-version="3.0" xml:lang="en">
<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-2026-3077</article-id>
<title-group>
<article-title>Constraining the Hydrogen Soil Sink and Photochemical Source: Insights from Atmospheric H&lt;sub&gt;2&lt;/sub&gt; Inversions (2003&amp;ndash;2023)</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Stroo</surname>
<given-names>Firmin T.</given-names>
<ext-link>https://orcid.org/0000-0001-9005-6822</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>Hooghiem</surname>
<given-names>Joram J. D.</given-names>
<ext-link>https://orcid.org/0000-0002-1850-4130</ext-link>
</name>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Krol</surname>
<given-names>Maarten C.</given-names>
<ext-link>https://orcid.org/0000-0002-3506-2477</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>Peters</surname>
<given-names>Wouter</given-names>
<ext-link>https://orcid.org/0000-0001-8166-2070</ext-link>
</name>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Centre for Isotope Research (CIO), Energy and Sustainability Research Institute Groningen (ESRIG) at University of Groningen, Groningen, The Netherlands</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>Department of Meteorology and Air Quality at Wageningen University &amp; Research, Wageningen, The Netherlands</addr-line>
</aff>
<aff id="aff3">
<label>3</label>
<addr-line>Institute for Marine and Atmospheric Research Utrecht at Utrecht University, Utrecht, The Netherlands</addr-line>
</aff>
<pub-date pub-type="epub">
<day>15</day>
<month>06</month>
<year>2026</year>
</pub-date>
<volume>2026</volume>
<fpage>1</fpage>
<lpage>43</lpage>
<permissions>
<copyright-statement>Copyright: &#x000a9; 2026 Firmin T. Stroo 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-2026-3077/">This article is available from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-3077/</self-uri>
<self-uri xlink:href="https://egusphere.copernicus.org/preprints/2026/egusphere-2026-3077/egusphere-2026-3077.pdf">The full text article is available as a PDF file from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-3077/egusphere-2026-3077.pdf</self-uri>
<abstract>
<p>Hydrogen (H&lt;sub&gt;2&lt;/sub&gt;) is expected to become an increasingly important energy carrier during the energy transition, likely leading to higher atmospheric H&lt;sub&gt;2 &lt;/sub&gt;levels due to losses during production, transport, storage and usage of hydrogen. Multiple studies have shown this could impact atmospheric composition through interactions with the hydroxyl radical. However, the magnitude of this impact remains uncertain due to large uncertainties in the global H&lt;sub&gt;2 &lt;/sub&gt;budget, particularly in the soil sink and photochemical source. To address this, we present a spatiotemporally resolved H&lt;sub&gt;2 &lt;/sub&gt;budget derived using atmospheric inversions with the TM5 chemical transport model. With this approach, we infer a global mean soil sink of 52.8 [47.8&amp;ndash;56.7] Tg yr&lt;sup&gt;&amp;minus;1&lt;/sup&gt; and a photochemical source of 34.6 [29.2&amp;ndash;38.2] Tg yr&lt;sup&gt;&amp;minus;1&lt;/sup&gt; over 2003&amp;ndash;2023. Relative to Ouyang et al. (2025), we estimate a soil sink that is 45 % and 35 % weaker in the Middle East and Oceania, and 45 % and 70 % stronger in South America and Russia, respectively. Our results further suggest that variability in the observed H&lt;sub&gt;2 &lt;/sub&gt;growth rate between 2003&amp;ndash;2023 was primarily driven by changes in the photochemical source from CH4 oxidation, together with a declining global soil sink at a mean rate of 0.23 Tg yr&lt;sup&gt;&amp;minus;2&lt;/sup&gt; . Finally, we infer a sensitivity of the soil sink to the El Ni&amp;ntilde;o&amp;ndash;Southern Oscillation, strongest over diffusion-limited soils in tropical South America, with increased uptake during drier El Ni&amp;ntilde;o conditions and reduced uptake during wetter La Ni&amp;ntilde;a conditions.</p>
</abstract>
<counts><page-count count="43"/></counts>
</article-meta>
</front>
<body/>
<back>
</back>
</article>