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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>
<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-2026-6528</article-id>
<title-group>
<article-title>Atmospheric observations reveal Alaskan wetland CH&lt;sub&gt;4&lt;/sub&gt; fluxes are up to threefold higher than process-based model estimates</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Liu</surname>
<given-names>Hanyu</given-names>
<ext-link>https://orcid.org/0009-0008-4252-0393</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>Miller</surname>
<given-names>Charles E.</given-names>
<ext-link>https://orcid.org/0000-0002-9380-4838</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>Sweeney</surname>
<given-names>Colm</given-names>
<ext-link>https://orcid.org/0000-0002-4517-0797</ext-link>
</name>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>McKain</surname>
<given-names>Kathryn</given-names>
<ext-link>https://orcid.org/0000-0002-8323-5758</ext-link>
</name>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Watts</surname>
<given-names>Jennifer D.</given-names>
</name>
<xref ref-type="aff" rid="aff4">
<sup>4</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Commane</surname>
<given-names>Róisín</given-names>
<ext-link>https://orcid.org/0000-0003-1373-1550</ext-link>
</name>
<xref ref-type="aff" rid="aff5">
<sup>5</sup>
</xref>
<xref ref-type="aff" rid="aff6">
<sup>6</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Schiferl</surname>
<given-names>Luke D.</given-names>
<ext-link>https://orcid.org/0000-0002-5047-2490</ext-link>
</name>
<xref ref-type="aff" rid="aff6">
<sup>6</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Zhang</surname>
<given-names>Zhen</given-names>
</name>
<xref ref-type="aff" rid="aff7">
<sup>7</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Poulter</surname>
<given-names>Benjamin</given-names>
<ext-link>https://orcid.org/0000-0002-9493-8600</ext-link>
</name>
<xref ref-type="aff" rid="aff8">
<sup>8</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Feng</surname>
<given-names>Leyang</given-names>
<ext-link>https://orcid.org/0000-0002-5426-8403</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>Chen</surname>
<given-names>Ao</given-names>
<ext-link>https://orcid.org/0000-0002-3604-3403</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>Huang</surname>
<given-names>Ziting</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>Gaeta</surname>
<given-names>Dylan C.</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>Morgan</surname>
<given-names>Kristan L.</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>Daniels</surname>
<given-names>William S.</given-names>
<ext-link>https://orcid.org/0000-0001-8752-5536</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>Li</surname>
<given-names>Qiulun</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>Melton</surname>
<given-names>Joe R.</given-names>
<ext-link>https://orcid.org/0000-0002-9414-064X</ext-link>
</name>
<xref ref-type="aff" rid="aff9">
<sup>9</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Yadav</surname>
<given-names>Vineet</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>Huntzinger</surname>
<given-names>Deborah</given-names>
<ext-link>https://orcid.org/0000-0003-2998-099X</ext-link>
</name>
<xref ref-type="aff" rid="aff10">
<sup>10</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Miller</surname>
<given-names>Scot M.</given-names>
<ext-link>https://orcid.org/0000-0003-4462-8126</ext-link>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Department of Environmental Health and Engineering, Johns Hopkins University, Baltimore, MD, USA</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA</addr-line>
</aff>
<aff id="aff3">
<label>3</label>
<addr-line>National Oceanic and Atmospheric Administration, Global Monitoring Laboratory, Boulder, CO, USA</addr-line>
</aff>
<aff id="aff4">
<label>4</label>
<addr-line>Woodwell Climate Research Center, Falmouth, MA, USA</addr-line>
</aff>
<aff id="aff5">
<label>5</label>
<addr-line>Department of Earth and Environmental Sciences, Columbia University, New York, NY, USA</addr-line>
</aff>
<aff id="aff6">
<label>6</label>
<addr-line>Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, USA</addr-line>
</aff>
<aff id="aff7">
<label>7</label>
<addr-line>Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China</addr-line>
</aff>
<aff id="aff8">
<label>8</label>
<addr-line>Spark Climate Solutions, San Francisco, CA, USA</addr-line>
</aff>
<aff id="aff9">
<label>9</label>
<addr-line>Environment and Climate Change Canada, Victoria, BC, Canada</addr-line>
</aff>
<aff id="aff10">
<label>10</label>
<addr-line>School of Earth and Sustainability, Northern Arizona University, Flagstaff, AZ, USA</addr-line>
</aff>
<pub-date pub-type="epub">
<day>09</day>
<month>11</month>
<year>2026</year>
</pub-date>
<volume>2026</volume>
<fpage>1</fpage>
<lpage>29</lpage>
<permissions>
<copyright-statement>Copyright: &#x000a9; 2026 Hanyu Liu 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-2026-6528/">This article is available from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-6528/</self-uri>
<self-uri xlink:href="https://egusphere.copernicus.org/preprints/2026/egusphere-2026-6528/egusphere-2026-6528.pdf">The full text article is available as a PDF file from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-6528/egusphere-2026-6528.pdf</self-uri>
<abstract>
<p>Amplified Arctic warming could substantially increase methane (CH&lt;sub&gt;4&lt;/sub&gt;) fluxes from high-latitudes by accelerating soil thaw and releasing soil organic carbon into the atmosphere. Yet, the magnitude and spatiotemporal patterns of current and future high-latitude CH&lt;sub&gt;4&lt;/sub&gt; fluxes remain highly uncertain. We estimate growing season (May to September) CH&lt;sub&gt;4&lt;/sub&gt; fluxes in Alaska from 2012 to 2017 using atmospheric observations from two NASA campaigns: the Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE) and Arctic-Carbon Atmospheric Profiles (Arctic-CAP). We couple these observations with an atmospheric transport model and a geostatistical inverse model to estimate the geographic distribution, seasonality, and inter-annual variability of CH&lt;sub&gt;4&lt;/sub&gt; fluxes. As part of this approach, we evaluate how well different state-of-the-art, process-based flux models compare to the inverse estimate of CH&lt;sub&gt;4&lt;/sub&gt; fluxes. We find that estimated statewide fluxes are a factor of 1.3 to 2.9 higher compared to different ensembles of process-based models. This discrepancy is largest across the North Slope of Alaska &amp;ndash; up to a factor of 6.5 when compared to one of the model ensembles. We do not find any statistically significant inter-annual variability (IAV) during years 2012&amp;ndash;2017, and the IAV in our estimate is generally consistent with process-based models. In addition, our analysis reveals that differences in inundation fraction mapping contribute to the magnitude discrepancies in current process-based models, and future improvements in inundation maps are essential to reduce uncertainties in CH&lt;sub&gt;4&lt;/sub&gt; flux estimates across high latitudes. These results provide an improved atmospheric constraint on regional CH&lt;sub&gt;4&lt;/sub&gt; flux estimates from northern wetlands under accelerated Arctic warming.</p>
</abstract>
<counts><page-count count="29"/></counts>
<funding-group>
<award-group id="gs1">
<funding-source>National Aeronautics and Space Administration</funding-source>
<award-id>#80NSSC22K1246</award-id>
</award-group>
<award-group id="gs2">
<funding-source>National Science Foundation</funding-source>
<award-id>#2237404</award-id>
</award-group>
<award-group id="gs3">
<funding-source>National Aeronautics and Space Administration</funding-source>
<award-id>#80NM0018D0004</award-id>
</award-group>
</funding-group>
</article-meta>
</front>
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