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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-2026-2510</article-id>
<title-group>
<article-title>A blue-band surface residual correction method for land aerosol optical depth retrieval from DQ-1 WSI</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Zhao</surname>
<given-names>Jingxuan</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>Wang</surname>
<given-names>Yujing</given-names>
</name>
<xref ref-type="aff" rid="aff4">
<sup>4</sup>
</xref>
<xref ref-type="aff" rid="aff5">
<sup>5</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Chen</surname>
<given-names>Hui</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>Zhang</surname>
<given-names>Mengjie</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>Wang</surname>
<given-names>Lili</given-names>
</name>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Yang</surname>
<given-names>Xingchuan</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>Dong</surname>
<given-names>Shuo</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>Zhao</surname>
<given-names>Wenji</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>Ma</surname>
<given-names>Pengfei</given-names>
</name>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>College of Resource Environment and Tourism, Capital Normal University, Beijing 100048, China</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>Ministry of Ecology and Environment Center for Satellite Application on Ecology and Environment State Environmental  Protection Key Laboratory of Satellite Remote Sensing, Beijing, 100094, China</addr-line>
</aff>
<aff id="aff3">
<label>3</label>
<addr-line>School of Geology and Geomatics, Tianjin Chengjian University, Tianjin, 300384, China</addr-line>
</aff>
<aff id="aff4">
<label>4</label>
<addr-line>Henan Institute of Geo-Environment Exploration Co., Ltd. Zhengzhou 450000, China</addr-line>
</aff>
<aff id="aff5">
<label>5</label>
<addr-line>Henan Institute of Geo-Environment Planning &amp; Design Co., Ltd. Zhengzhou 450000, China</addr-line>
</aff>
<pub-date pub-type="epub">
<day>18</day>
<month>08</month>
<year>2026</year>
</pub-date>
<volume>2026</volume>
<fpage>1</fpage>
<lpage>31</lpage>
<permissions>
<copyright-statement>Copyright: &#x000a9; 2026 Jingxuan Zhao 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-2026-2510/">This article is available from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-2510/</self-uri>
<self-uri xlink:href="https://egusphere.copernicus.org/preprints/2026/egusphere-2026-2510/egusphere-2026-2510.pdf">The full text article is available as a PDF file from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-2510/egusphere-2026-2510.pdf</self-uri>
<abstract>
<p>Surface reflectance prior uncertainty remains a major source of error in land aerosol optical depth (AOD) retrieval, particularly over complex surfaces and for newly launched satellite sensors lacking long-term observations for constructing stable surface priors. Here, we develop a hybrid AOD retrieval framework for the DQ-1 Wide Swath Imager (WSI) that integrates a static surface reflectance prior, machine-learning-based blue-band surface residual correction, and a physically based lookup-table (LUT) inversion. A multi-band static surface prior is first constructed from quality-controlled clear-sky observations under low-aerosol-loading conditions. Rather than directly predicting AOD, a random forest model is used to estimate the residual between the static and reference surface terms at 0.443 &amp;mu;m from the static blue-band prior, top-of-atmosphere reflectance, NDVI, viewing geometry, and elevation. The corrected blue-band surface term is then propagated through the conventional LUT retrieval, thereby retaining the&amp;nbsp; physical aerosol inversion framework while using machine learning only to mitigate surface-prior&amp;nbsp; mismatch. MCD19A2 AOD is used exclusively in the offline stage to support the construction of&amp;nbsp; LUT-derived reference surface terms and for independent cross-product spatial consistency assessment, whereas AERONET observations provide the primary ground-based validation. Relative to the static-prior LUT retrieval, residual correction reduces the AERONET-based RMSE from 0.256 to 0.107 and mean bias error from 0.187 to 0.059, while increasing the fraction of retrievals within the expected error envelope from 14.8 % to 55.6 %. Evaluation on a held-out scene further demonstrates that the model generalizes the relationship between static-prior error and the LUT-derived reference surface term, reducing the blue-band surface-term MAE from 0.0088 to 0.0044. On dates excluded from model training and internal validation, the retrieved DQ-1 WSI AOD also exhibits strong regional spatial consistency with MCD19A2 across 200,507 collocated pixels (R = 0.863, RMSE = 0.131, MAE = 0.093, MBE = 0.012, and regression slope = 0.99). These results indicate that the performance improvement primarily arises from alleviating blue-band surface-prior mismatch within the physical LUT inversion rather than from direct empirical fitting of AOD. The proposed framework therefore provides a physically interpretable strategy for improving land AOD retrieval from DQ-1 WSI over springtime complex surfaces and offers a transferable solution for new wide-swath sensors for which robust long-term surface&amp;nbsp; reflectance priors are not yet available.</p>
</abstract>
<counts><page-count count="31"/></counts>
<funding-group>
<award-group id="gs1">
<funding-source>Natural Science Foundation of Beijing Municipality</funding-source>
<award-id>L241082</award-id>
</award-group>
</funding-group>
</article-meta>
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