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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-2026-4968</article-id>
<title-group>
<article-title>Representativeness of TROPOMI tropospheric NO&lt;sub&gt;2&lt;/sub&gt; columns near Asian airports constrained by IAGOS airborne measurements</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Lim</surname>
<given-names>Hyunkwang</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>Fujinawa</surname>
<given-names>Tamaki</given-names>
<ext-link>https://orcid.org/0000-0003-3506-0137</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>Sugita</surname>
<given-names>Takafumi</given-names>
<ext-link>https://orcid.org/0000-0002-0508-7040</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>Inomata</surname>
<given-names>Satoshi</given-names>
<ext-link>https://orcid.org/0000-0002-8971-0740</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>Tanimoto</surname>
<given-names>Hiroshi</given-names>
<ext-link>https://orcid.org/0000-0002-5424-9923</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>Mahnke</surname>
<given-names>Christoph</given-names>
<ext-link>https://orcid.org/0000-0003-2606-1680</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>Petzold</surname>
<given-names>Andreas</given-names>
<ext-link>https://orcid.org/0000-0002-2504-1680</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>Bundke</surname>
<given-names>Ulrich</given-names>
<ext-link>https://orcid.org/0000-0001-5484-8099</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>Kanaya</surname>
<given-names>Yugo</given-names>
<ext-link>https://orcid.org/0000-0001-9354-3116</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>Kasai</surname>
<given-names>Yasuko</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>Sato</surname>
<given-names>Tomohiro O.</given-names>
<ext-link>https://orcid.org/0000-0002-0123-9393</ext-link>
</name>
<xref ref-type="aff" rid="aff4">
<sup>4</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Park</surname>
<given-names>Sang Seo</given-names>
</name>
<xref ref-type="aff" rid="aff5">
<sup>5</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Kim</surname>
<given-names>Minseok</given-names>
</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>Lee</surname>
<given-names>Yun Gon</given-names>
<ext-link>https://orcid.org/0000-0002-1187-6206</ext-link>
</name>
<xref ref-type="aff" rid="aff7">
<sup>7</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Jeong</surname>
<given-names>Ukkyo</given-names>
<ext-link>https://orcid.org/0000-0001-8124-1495</ext-link>
</name>
<xref ref-type="aff" rid="aff8">
<sup>8</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Earth System Division, National Institute of Environmental Studies, Ibariki 305-8506, Japan</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>Forschungszentrum Jülich GmbH (FZJ), Institute of Climate and Energy Systems: Troposphere (ICE-3), Jülich 52428,  Germany</addr-line>
</aff>
<aff id="aff3">
<label>3</label>
<addr-line>Earth Surface System Research Center, Japan Agency for Marine-Earth Science and Technology, Kanagawa, 236‑0001,  Japan</addr-line>
</aff>
<aff id="aff4">
<label>4</label>
<addr-line>Terahertz Technology Research Center, National Institute of Information and Communications Technology, Tokyo,  184-8795, Japan</addr-line>
</aff>
<aff id="aff5">
<label>5</label>
<addr-line>Department of Civil, Urban, Earth, and Environmental Engineering, Ulsan National Institute of Science and Technology, Ulsan, 44919, Republic of Korea</addr-line>
</aff>
<aff id="aff6">
<label>6</label>
<addr-line>AI-Transformed Aerospace InnoCORE Research Center, Korea Advanced Institute of Science and Technology,  (KAIST), Daejeon 34141, Republic of Korea</addr-line>
</aff>
<aff id="aff7">
<label>7</label>
<addr-line>Department of Earth, Environmental &amp; Space Sciences, Chungnam National University, Daejeon 34134, Republic of Korea</addr-line>
</aff>
<aff id="aff8">
<label>8</label>
<addr-line>Division of Earth Environmental System Science, Major of Spatial Information Engineering, Pukyong National  University, Pusan, 48513, Republic of Korea</addr-line>
</aff>
<pub-date pub-type="epub">
<day>11</day>
<month>09</month>
<year>2026</year>
</pub-date>
<volume>2026</volume>
<fpage>1</fpage>
<lpage>28</lpage>
<permissions>
<copyright-statement>Copyright: &#x000a9; 2026 Hyunkwang Lim 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-2026-4968/">This article is available from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-4968/</self-uri>
<self-uri xlink:href="https://egusphere.copernicus.org/preprints/2026/egusphere-2026-4968/egusphere-2026-4968.pdf">The full text article is available as a PDF file from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-4968/egusphere-2026-4968.pdf</self-uri>
<abstract>
<p>Tropospheric NO₂ data retrievals from the satellite-borne TROPOspheric Monitoring Instrument (TROPOMI) are sensitive to the vertical profile assumed in the air mass factor (AMF) calculation, especially in polluted lower-tropospheric environments. This study investigated the use of aircraft and ground-based profile information to evaluate this sensitivity near five major airports. We combined TROPOMI tropospheric NO₂ vertical column densities (VCDs), land-based Pandora observations, and airplane-based In-service Aircraft for a Global Observing System (IAGOS) descent profiles for selected airport&amp;ndash;Pandora pairs in Japan, South Korea, and Thailand from March to July 2025. Before applying profile-based AMF recalculations, we examined whether the TROPOMI NO₂ field around each Pandora site was representative of that around the corresponding airport. The airport- and Pandora-region time series were generally coherent, although their mean NO₂ levels differed, indicating that temporal consistency and absolute spatial representativeness need to be considered separately.&lt;/p&gt;
&lt;p&gt;The lower part of the a priori NO₂ profile obtained by the TM5-MP model was then replaced with IAGOS-derived profiles to recalculate TROPOMI AMFs and VCDs. The IAGOS-profile recalculation reduced the overall low bias relative to Pandora data and improved several validation metrics, but the response differed by site. Improvements were most evident where the IAGOS descent profiles, Pandora site, and satellite-observed NO₂ field sampled similar environments. In contrast, weaker or degraded performance occurred when the aircraft profiles represented an air mass different from that influencing the Pandora-acquired column. The Pandora-scaled-profile case produced the closest agreement with Pandora results, but the comparison is more suitable as a profile-sensitivity test rather than an independent validation. Residual diagnosis showed that the remaining differences after the Pandora-scaled-profile recalculation were not mainly controlled by horizontal NO₂ heterogeneity, pixel sampling density, mean quality assurance value, or the magnitude of the AMF correction. A slant column density (SCD)-equivalent closure analysis further suggested that profile replacement alone cannot fully reconcile TROPOMI and Pandora columns, because the recalculated VCD still depends on the TROPOMI effective tropospheric SCD and other non-profile retrieval inputs. These findings demonstrate the value of IAGOS and Pandora lower-tropospheric profile information for diagnosing TROPOMI NO₂ AMF uncertainty near airports, while underscoring the need to account for slant-column retrieval uncertainty, cloud and surface effects, and spatial representativeness.</p>
</abstract>
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</article-meta>
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