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@ARTICLE{vanDiepen:1041802,
      author       = {van Diepen, Kevin H. H. and Kaiser, Elias and Hartogensis,
                      Oscar K. and Graf, Alexander and de Arellano, Jordi
                      Vilà-Guerau and Moene, Arnold F.},
      title        = {{W}hen do clouds and aerosols lead to higher canopy
                      photosynthesis?},
      journal      = {Agricultural and forest meteorology},
      volume       = {370},
      issn         = {0168-1923},
      address      = {Amsterdam [u.a.]},
      publisher    = {Elsevier},
      reportid     = {FZJ-2025-02438},
      pages        = {110597 -},
      year         = {2025},
      abstract     = {Clouds and aerosols can increase canopy photosynthesis
                      relative to clear-sky values through changes in total and
                      diffuse solar radiation: the diffuse fertilization effect
                      (DFE). DFE varies across observational sites due to (a)
                      inconsistent definitions and quantifications of DFE, (b)
                      unexplored relationships between DFE and cloudiness type,
                      and (c) insufficient knowledge of the effect of site
                      characteristics. We showed that: DFE definitions vary, DFE
                      quantifications do not connect to existing definitions or do
                      not isolate the causal factor, and a systematic protocol to
                      quantify DFE is lacking. A new theoretical framework served
                      to clarify the relation between DFE definitions, and showed
                      how DFE varies with cloudiness types and site
                      characteristics. We proposed guidelines for a systematic DFE
                      quantification across studies, and which aim to isolate the
                      causal factor of DFE.Applying our framework to observations
                      of canopy photosynthesis, solar radiation and cloudiness
                      types we quantified DFE at daily and sub-daily time scales.
                      We showed for the first time how DFE varies with cloudiness
                      type, due to the varying trade-off between diffuse radiation
                      and total solar radiation. Using an observation-driven
                      canopy photosynthesis model, we showed that the DFE varies
                      with site characteristics and time of day. The DFE responded
                      strongly to leaf area index, canopy nitrogen distribution,
                      leaf orientation and leaf transmittance, with leaf area
                      index and leaf orientation driving DFE occurrences at our
                      site. Our study emphasizes the importance of quantifying the
                      DFE systematically and accurately across observational sites
                      and highlights the need for information on cloudiness
                      climatology and site characteristics.},
      cin          = {IBG-3},
      ddc          = {550},
      cid          = {I:(DE-Juel1)IBG-3-20101118},
      pnm          = {2173 - Agro-biogeosystems: controls, feedbacks and impact
                      (POF4-217) / TERENO - Terrestrial Environmental
                      Observatories (TERENO-2008) / DFG project G:(GEPRIS)40997345
                      - Projektdatenbank und Datenmanagement (INF (Z01))
                      (40997345)},
      pid          = {G:(DE-HGF)POF4-2173 / G:(DE-HGF)TERENO-2008 /
                      G:(GEPRIS)40997345},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:001494777800001},
      doi          = {10.1016/j.agrformet.2025.110597},
      url          = {https://juser.fz-juelich.de/record/1041802},
}