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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-2025-6057</article-id>
<title-group>
<article-title>Temporal variability of NO&lt;sub&gt;&lt;em&gt;x&lt;/em&gt;&lt;/sub&gt; emissions from power plants: a comparison of satellite- and inventory-based estimates</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Kuhlmann</surname>
<given-names>Gerrit</given-names>
<ext-link>https://orcid.org/0000-0002-7021-4712</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>Koene</surname>
<given-names>Erik Franciscus Maria</given-names>
<ext-link>https://orcid.org/0000-0002-2778-4066</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>Schooling</surname>
<given-names>Chloe Natasha</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>Palmer</surname>
<given-names>Paul Ian</given-names>
<ext-link>https://orcid.org/0000-0002-1487-0969</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>López</surname>
<given-names>Òscar Collado</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>Guevara</surname>
<given-names>Marc</given-names>
<ext-link>https://orcid.org/0000-0001-9727-8583</ext-link>
</name>
<xref ref-type="aff" rid="aff4">
<sup>4</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Empa, Laboratory for Air Pollution / Environmental Technology, Dübendorf, Switzerland</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>School of GeoSciences, University of Edinburgh, Edinburgh, United Kingdom</addr-line>
</aff>
<aff id="aff3">
<label>3</label>
<addr-line>National Centre for Earth Observation, University of Edinburgh, Edinburgh, United Kingdom</addr-line>
</aff>
<aff id="aff4">
<label>4</label>
<addr-line>Barcelona Supercomputing Center, Barcelona, Spain</addr-line>
</aff>
<pub-date pub-type="epub">
<day>14</day>
<month>01</month>
<year>2026</year>
</pub-date>
<volume>2026</volume>
<fpage>1</fpage>
<lpage>22</lpage>
<permissions>
<copyright-statement>Copyright: &#x000a9; 2026 Gerrit Kuhlmann 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-2025-6057/">This article is available from https://egusphere.copernicus.org/preprints/2026/egusphere-2025-6057/</self-uri>
<self-uri xlink:href="https://egusphere.copernicus.org/preprints/2026/egusphere-2025-6057/egusphere-2025-6057.pdf">The full text article is available as a PDF file from https://egusphere.copernicus.org/preprints/2026/egusphere-2025-6057/egusphere-2025-6057.pdf</self-uri>
<abstract>
<p>Satellite observations of nitrogen dioxide (NO&lt;sub&gt;2&lt;/sub&gt;) are a valuable tool for estimating nitrogen oxides (NO&lt;em&gt;&lt;sub&gt;x&lt;/sub&gt;&lt;/em&gt;) emissions from point sources and can support carbon dioxide (CO&lt;sub&gt;2&lt;/sub&gt;) monitoring through emission ratios. We assess the capability of TROPOMI NO&lt;sub&gt;2&lt;/sub&gt; measurements to quantify the temporal variability of NO&lt;em&gt;&lt;sub&gt;x&lt;/sub&gt;&lt;/em&gt; emissions from eighteen power plants in&amp;nbsp;Europe and the United States. Using the cross-sectional flux (CSF) method implemented in the &lt;em&gt;ddeq&lt;/em&gt; Python library (version 1.1), we derive top-down emissions and compare two NO&lt;em&gt;&lt;sub&gt;x&lt;/sub&gt;&lt;/em&gt; chemistry corrections approaches: a &amp;ldquo;local&amp;rdquo; method based on MicroHH and a &amp;ldquo;global&amp;rdquo; method based on GEOS-Chem simulations. Annual top-down estimates using the local approach agree well with bottom-up estimates from the CORSO point source database, with a mean bias of 9 &amp;plusmn; 20 % when aggregating sources within 30 km. A regression analysis yields a slope of 1.05 &amp;plusmn; 0.17 and a coefficient of determination of 0.68. The local correction yields emissions that are 58 &amp;plusmn; 8 % higher than the global approach. Satellite-based estimates successfully captured seasonal and short-term variability in bottom-up emissions estimated from electricity generation in Europe and continuous emissions monitoring systems (CEMS) in the USA. However, limitations remain due to reduced winter coverage, emissions below the detection limit, overlapping plumes, and uncertainties in NO&lt;em&gt;&lt;sub&gt;x&lt;/sub&gt;&lt;/em&gt; chemistry corrections especially for non-isolated facilities. Overall, our findings demonstrate that satellite NO&lt;sub&gt;2&lt;/sub&gt; observations can effectively monitor the seasonality of NO&lt;em&gt;&lt;sub&gt;x&lt;/sub&gt;&lt;/em&gt; emissions from power plants. Addressing remaining uncertainties will be essential for future emission monitoring systems and upcoming satellite missions targeting both NO&lt;sub&gt;2&lt;/sub&gt; and CO&lt;sub&gt;2&lt;/sub&gt;.</p>
</abstract>
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<funding-group>
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<funding-source>HORIZON EUROPE Digital, Industry and Space</funding-source>
<award-id>101082194</award-id>
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<funding-source>Staatssekretariat für Bildung, Forschung und Innovation</funding-source>
<award-id>22.00422</award-id>
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<funding-source>National Centre for Earth Observation</funding-source>
<award-id>NE/R016518/1</award-id>
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</funding-group>
</article-meta>
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