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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-2026-4740</article-id>
<title-group>
<article-title>Explaining observed surface radiation trends 2001&amp;ndash;2023 on Alaska&apos;s North Slope</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Bertrand</surname>
<given-names>Leah J.</given-names>
<ext-link>https://orcid.org/0009-0000-0160-7558</ext-link>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Kay</surname>
<given-names>Jennifer E.</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>de Boer</surname>
<given-names>Gijs</given-names>
<ext-link>https://orcid.org/0000-0003-4652-7150</ext-link>
</name>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Department of Atmospheric and Oceanic Sciences, University of Colorado at Boulder, Boulder, CO, United States of America</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>Cooperative Institute for Research in Environmental Sciences, Boulder, CO, United States of America</addr-line>
</aff>
<aff id="aff3">
<label>3</label>
<addr-line>Environmental Science and Technologies Department, Brookhaven National Laboratory, Upton, NY, USA</addr-line>
</aff>
<pub-date pub-type="epub">
<day>28</day>
<month>08</month>
<year>2026</year>
</pub-date>
<volume>2026</volume>
<fpage>1</fpage>
<lpage>25</lpage>
<permissions>
<copyright-statement>Copyright: &#x000a9; 2026 Leah J. Bertrand 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-2026-4740/">This article is available from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-4740/</self-uri>
<self-uri xlink:href="https://egusphere.copernicus.org/preprints/2026/egusphere-2026-4740/egusphere-2026-4740.pdf">The full text article is available as a PDF file from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-4740/egusphere-2026-4740.pdf</self-uri>
<abstract>
<p>Changes in surface radiation are a key contributor to Arctic surface warming. However, the details of Arctic surface radiation change are not fully known due to a lack of multi-decadal observations. Here, we leverage 23 years (2001&amp;ndash;2023) of ground-based observations at two neighboring coastal tundra sites on the North Slope of Alaska (NSA) to explain surface radiation change. US Department of Energy Atmospheric Radiation Measurement (ARM) and National Oceanic and Atmospheric Administration (NOAA) facilities in Utgiagvik, Alaska have documented warming (0.9 K/decade since 2001) and surface radiation change. Surface downwelling longwave radiation increases year-round. Surface downwelling and net shortwave radiation decrease during sunlit months (April&amp;ndash;September). Decreasing net shortwave radiation is driven by changing cloud properties and increasing surface albedo over exposed tundra in mid-summer. Increasing downwelling longwave radiation during both sunlit and dark months (October&amp;ndash;March) is driven by atmospheric warming, increasing water vapor, and changing cloud properties. Atmospheric warming and increasing water vapor explain about half the total observed increase in downwelling longwave radiation, while changing cloud properties explain the rest. Assessed cloud drivers (liquid water path, cloud cover, and low cloud fraction) explain increasing longwave radiation during sunlit months but are insufficient during dark months. Changes in assessed cloud drivers increased longwave radiation in all seasons except SON, when there was no change. These results reveal substantial surface radiative changes on the NSA, where cloud radiative effect changes amplify surface warming during dark months and dampen it during sunlit months.</p>
</abstract>
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<funding-group>
<award-group id="gs1">
<funding-source>National Aeronautics and Space Administration</funding-source>
<award-id>849K995</award-id>
</award-group>
<award-group id="gs2">
<funding-source>Cooperative Institute for Research in Environmental Sciences</funding-source>
<award-id>Graduate Student Research Award Program</award-id>
</award-group>
</funding-group>
</article-meta>
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