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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-2026-5990</article-id>
<title-group>
<article-title>Assessment of the PACE/SPEXone Aerosol Layer Height (ALH) Retrievals and Intercomparison with EarthCARE/ATLID Observations</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Voudouri</surname>
<given-names>Kalliopi Artemis</given-names>
<ext-link>https://orcid.org/0000-0001-8298-5103</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>Karipis</surname>
<given-names>Andreas</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>Tsekeri</surname>
<given-names>Alexandra</given-names>
<ext-link>https://orcid.org/0000-0002-3745-225X</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>Hasekamp</surname>
<given-names>Otto</given-names>
<ext-link>https://orcid.org/0000-0002-1494-2539</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>Knobelspiesse</surname>
<given-names>Kirk</given-names>
<ext-link>https://orcid.org/0000-0001-5986-1751</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>Gao</surname>
<given-names>Meng</given-names>
<ext-link>https://orcid.org/0000-0002-5818-1639</ext-link>
</name>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
<xref ref-type="aff" rid="aff8">
<sup>8</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Gasso</surname>
<given-names>Santiago</given-names>
<ext-link>https://orcid.org/0000-0002-6872-0018</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>van Zadelhoff</surname>
<given-names>Gerd-jan</given-names>
<ext-link>https://orcid.org/0000-0002-1974-1998</ext-link>
</name>
<xref ref-type="aff" rid="aff5">
<sup>5</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Tsikerdekis</surname>
<given-names>Athanasios</given-names>
<ext-link>https://orcid.org/0000-0002-4694-2015</ext-link>
</name>
<xref ref-type="aff" rid="aff5">
<sup>5</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Fu</surname>
<given-names>Guangliang</given-names>
<ext-link>https://orcid.org/0000-0001-8916-0243</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>Lopatin</surname>
<given-names>Anton</given-names>
</name>
<xref ref-type="aff" rid="aff6">
<sup>6</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Dubovik</surname>
<given-names>Oleg</given-names>
<ext-link>https://orcid.org/0000-0003-3482-6460</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>Malina</surname>
<given-names>Edward</given-names>
<ext-link>https://orcid.org/0000-0002-1055-4598</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>Marinou</surname>
<given-names>Eleni</given-names>
<ext-link>https://orcid.org/0000-0003-2631-6057</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>Amiridis</surname>
<given-names>Vassilis</given-names>
<ext-link>https://orcid.org/0000-0002-1544-7812</ext-link>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>IAASARS, National Observatory of Athens, Greece</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>Space Research Organization Netherlands (NWO-I/SRON), Leiden, the Netherlands</addr-line>
</aff>
<aff id="aff3">
<label>3</label>
<addr-line>Ocean Ecology Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA</addr-line>
</aff>
<aff id="aff4">
<label>4</label>
<addr-line>Goddard Earth Science and Technology Center, University of Maryland Baltimore County, Baltimore, Maryland, USA</addr-line>
</aff>
<aff id="aff5">
<label>5</label>
<addr-line>Royal Netherlands Meteorological Institute, De Bilt, Netherlands</addr-line>
</aff>
<aff id="aff6">
<label>6</label>
<addr-line>GRASP SAS, Lille, 59000, France</addr-line>
</aff>
<aff id="aff7">
<label>7</label>
<addr-line>Laboratoire d’Optique Atmosphérique, CNRS/Université de Lille, Villeneuve-d’Ascq, 59650, France</addr-line>
</aff>
<aff id="aff8">
<label>8</label>
<addr-line>Science Systems and Applications, Inc., Greenbelt, MD, USA</addr-line>
</aff>
<aff id="aff9">
<label>9</label>
<addr-line>European Space Agency (ESA/ESRIN), 00044 Frascati, Italy</addr-line>
</aff>
<pub-date pub-type="epub">
<day>13</day>
<month>10</month>
<year>2026</year>
</pub-date>
<volume>2026</volume>
<fpage>1</fpage>
<lpage>30</lpage>
<permissions>
<copyright-statement>Copyright: &#x000a9; 2026 Kalliopi Artemis Voudouri 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-2026-5990/">This article is available from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-5990/</self-uri>
<self-uri xlink:href="https://egusphere.copernicus.org/preprints/2026/egusphere-2026-5990/egusphere-2026-5990.pdf">The full text article is available as a PDF file from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-5990/egusphere-2026-5990.pdf</self-uri>
<abstract>
<p>Here, we present the first evaluation of the PACE/SPEXone aerosol layer height (ALH) products over oceanic regions, assessing retrievals from the two independent algorithms and their products, RemoTAP and FastMAPOL, against aerosol layer heights derived from EarthCARE/ATLID. The ATLID aerosol layer heights are calculated using a center-of-mass (COM) approach applied to aerosol extinction profiles. The selected oceanic regions provide insight on the PACE/SPEXone ALH retrieval performance, highlighting its sensitivity to the aerosol optical depth (AOD) loading and the aerosol vertical structure. Better agreement is observed over the Mediterranean region, where dust and mixed-dust aerosol types dominate. The RemoTAP and FastMAPOL retrievals show correlation coefficients of R = 0.30 and R = 0.60, with corresponding mean absolute errors of 1.12 and 1.07 km, respectively. Conversely, weaker correlations are found over the South Atlantic and Indian Ocean regions. Overall, global statistics indicate moderate agreement between SPEXone and ATLID ALH products, showing the dependence on the aerosol vertical distribution. We conclude that improved consistency is found for cases with strong agreement between SPEXone and EarthCARE AOD retrievals, particularly under higher aerosol loading conditions (AOD &amp;gt; 0.1). We further examine the impact of different ALH definitions by applying alternative Gaussian-fit approaches to the ATLID profiles, which leads to a slight improvement in the agreement between active and passive ALH estimates.</p>
</abstract>
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<funding-group>
<award-group id="gs1">
<funding-source>European Space Agency</funding-source>
<award-id>4000142902/23/I-NS</award-id>
</award-group>
</funding-group>
</article-meta>
</front>
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