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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-2026-1898</article-id>
<title-group>
<article-title>Canopy temperatures in computationally expensive crop models: A resource-efficient emulator approach applied in LPJmL (version 5.9.18)</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Hemmen</surname>
<given-names>Marie</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>Webber</surname>
<given-names>Heidi</given-names>
</name>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
<xref ref-type="aff" rid="aff4">
<sup>4</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>von Bloh</surname>
<given-names>Werner</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>Heinke</surname>
<given-names>Jens</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>Müller</surname>
<given-names>Christoph</given-names>
<ext-link>https://orcid.org/0000-0002-9491-3550</ext-link>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Potsdam Institute for Climate lmpact Research (PIK), Member of the Leibniz Association, P.O. Box 60 12 03, 14412 Potsdam, Germany</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>Humboldt-Universität zu Berlin (HU), Albrecht Daniel Thaer-Institut für Agrar- und Gartenbauwissenschaften, Berlin, Germany</addr-line>
</aff>
<aff id="aff3">
<label>3</label>
<addr-line>Leibniz Centre for Agricultural Landscape Research (ZALF), Müncheberg, Germany</addr-line>
</aff>
<aff id="aff4">
<label>4</label>
<addr-line>Institute of Environmental Sciences, Brandenburg University of Technology, Cottbus, Germany</addr-line>
</aff>
<pub-date pub-type="epub">
<day>18</day>
<month>05</month>
<year>2026</year>
</pub-date>
<volume>2026</volume>
<fpage>1</fpage>
<lpage>32</lpage>
<permissions>
<copyright-statement>Copyright: &#x000a9; 2026 Marie Hemmen 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-2026-1898/">This article is available from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-1898/</self-uri>
<self-uri xlink:href="https://egusphere.copernicus.org/preprints/2026/egusphere-2026-1898/egusphere-2026-1898.pdf">The full text article is available as a PDF file from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-1898/egusphere-2026-1898.pdf</self-uri>
<abstract>
<p>Crop yields are determined by multiple process chains that respond to environmental conditions. The very complex interactions between the different processes as well as the effects of isolated and combined process-level signals on final yields can be examined with process-based models. One of the key signals for crop development and growth dynamics is temperature, which is subject to change under global warming. While some crop models compute temperatures at the canopy level, others take 2 m air temperatures as input. However, the two temperatures can deviate significantly, potentially leading to different process responses when the less accurate 2 m air temperatures are used. This particularly applies to high-temperature processes that exhibit nonlinear dynamics and are very sensitive to small temperature variations. For global models, a major limitation is the computational resources required by suitable canopy temperature approaches. In this study we present computationally efficient emulators based on a complex energy balance approach (EBSC) to simulate daily mean and maximum canopy temperatures of twelve different crops. The emulators are statistical models that include six variables describing weather conditions and crop status. Furthermore, the emulators contain interaction terms to consider the response of canopy temperature on interactions between the variables. We apply and evaluate the emulators in the global, process-based Lund-Potsdam-Jena managed Land (LPJmL) model and show that the emulator approach reproduces observed canopy heating and cooling effects depending on the water and nitrogen status of wheat. Furthermore, we compare the simulated daily mean and daily maximum canopy temperatures of all twelve crops to a global dataset of ERA5 skin temperatures. We find that, for daily mean temperatures, 2 m air temperatures are the better approximation of skin temperatures than the simulated canopy temperatures, whereas for daily maximum temperatures simulated canopy temperatures consistently outperform 2 m air temperatures in terms of bias and nonunity slope. Our results indicate that heat effects are substantially underestimated with 2 m air temperatures, while they are significantly better captured with simulated canopy temperatures. This suggests that replacing the 2 m air temperature input by simulated canopy temperatures considerably improves the ability to model high temperature impacts on crop growth.</p>
</abstract>
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<funding-group>
<award-group id="gs1">
<funding-source>Deutsche Bundesstiftung Umwelt</funding-source>
<award-id>AZ20021/707</award-id>
</award-group>
<award-group id="gs2">
<funding-source>Bundesministerium für Forschung, Technologie und Raumfahrt</funding-source>
<award-id>FKZ 01LS2105A</award-id>
</award-group>
<award-group id="gs3">
<funding-source>Leibniz-Gemeinschaft</funding-source>
<award-id>P102/2020</award-id>
</award-group>
<award-group id="gs4">
<funding-source>Deutsche Forschungsgemeinschaft</funding-source>
<award-id>470400637</award-id>
</award-group>
<award-group id="gs5">
<funding-source>HORIZON EUROPE Climate, Energy and Mobility</funding-source>
<award-id>101137601</award-id>
</award-group>
<award-group id="gs6">
<funding-source>Future of Life Institute</funding-source>
<award-id>CODEC</award-id>
</award-group>
</funding-group>
</article-meta>
</front>
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