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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-2025-1559</article-id>
<title-group>
<article-title>Global atmospheric hydrogen chemistry and long-term source-sink budget simulation with the EMAC v2.55 model</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Surawski</surname>
<given-names>Nic</given-names>
<ext-link>https://orcid.org/0000-0003-2584-1044</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>Steil</surname>
<given-names>Benedikt</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>Brühl</surname>
<given-names>Christoph</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>Gromov</surname>
<given-names>Sergey</given-names>
<ext-link>https://orcid.org/0000-0002-2542-3005</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>Klingmüller</surname>
<given-names>Klaus</given-names>
<ext-link>https://orcid.org/0000-0002-8425-8150</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>Martin</surname>
<given-names>Anna</given-names>
<ext-link>https://orcid.org/0009-0009-1822-142X</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>Pozzer</surname>
<given-names>Andrea</given-names>
<ext-link>https://orcid.org/0000-0003-2440-6104</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>Lelieveld</surname>
<given-names>Jos</given-names>
<ext-link>https://orcid.org/0000-0001-6307-3846</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-group><aff id="aff1">
<label>1</label>
<addr-line>Centre for Green Technology, University of Technology Sydney, Gadigal Country, NSW 2007, Australia</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>Atmospheric Chemistry Department, Max Planck Institute for Chemistry, 55128 Mainz, Germany</addr-line>
</aff>
<aff id="aff3">
<label>3</label>
<addr-line>Climate and Atmosphere Research Center, The Cyprus Institute, Nicosia, Cyprus</addr-line>
</aff>
<pub-date pub-type="epub">
<day>12</day>
<month>05</month>
<year>2025</year>
</pub-date>
<volume>2025</volume>
<fpage>1</fpage>
<lpage>29</lpage>
<permissions>
<copyright-statement>Copyright: &#x000a9; 2025 Nic Surawski et al.</copyright-statement>
<copyright-year>2025</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/2025/egusphere-2025-1559/">This article is available from https://egusphere.copernicus.org/preprints/2025/egusphere-2025-1559/</self-uri>
<self-uri xlink:href="https://egusphere.copernicus.org/preprints/2025/egusphere-2025-1559/egusphere-2025-1559.pdf">The full text article is available as a PDF file from https://egusphere.copernicus.org/preprints/2025/egusphere-2025-1559/egusphere-2025-1559.pdf</self-uri>
<abstract>
<p>In this study, we use an earth system model with detailed atmospheric chemistry (EMAC v2.55.2) to undertake simulations of hydrogen (H&lt;sub&gt;2&lt;/sub&gt;) atmospheric dynamics. Long-term simulations were performed globally with a horizontal resolution of 1.9 degrees with results being compared with observational data from 56 stations in the National Oceanic and Atmospheric Administration (NOAA) Global Monitoring Laboratory (GML) Carbon Cycle Cooperative Global Air Sampling Network. We introduced H&lt;sub&gt;2&lt;/sub&gt; sources and sinks, the latter through a soil uptake scheme, that accounts for bacterial consumption. The model thus accounts for detailed H&lt;sub&gt;2&lt;/sub&gt; and methane (CH&lt;sub&gt;4&lt;/sub&gt;) flux boundary conditions. Results from the EMAC model are accurate and predict the magnitude, amplitude and interhemispheric seasonality of the annual hydrogen cycle at most observational stations. Time series comparison of EMAC and observational data produces Pearson correlation coefficients in excess of 0.9 at eight stations that experience well-mixed air masses free from direct anthropogenic perturbation. A further 23 stations yielded correlation coefficients between 0.7&amp;ndash;0.9 in remote tropical or mid-latitude locations. The quality of model predictions is reduced in anthropogenically highly polluted stations in east Asia and the Mediterranean region and stations impacted by peat fire emissions in Indonesia, as local and incidental emissions are difficult to capture. Our H&lt;sub&gt;2&lt;/sub&gt; budget corroborates bottom-up estimates in the literature in terms of source and sink strengths and overall atmospheric burden. By realistically simulating hydroxyl radicals in the atmosphere, we show that the EMAC model is a capable tool for undertaking high accuracy simulation of H&lt;sub&gt;2&lt;/sub&gt; at global scale. Future research applications could target the impact of potentially significant natural and anthropogenic H&lt;sub&gt;2&lt;/sub&gt; sources on air quality and climate, reducing uncertainties in the H&lt;sub&gt;2&lt;/sub&gt; soil sink and impacts of H&lt;sub&gt;2&lt;/sub&gt; release on the future oxidising capacity of the atmosphere.</p>
</abstract>
<counts><page-count count="29"/></counts>
<funding-group>
<award-group id="gs1">
<funding-source>Commonwealth Scientific and Industrial Research Organisation</funding-source>
<award-id>PRO23-18036</award-id>
</award-group>
</funding-group>
</article-meta>
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