A new empirical model to estimate hourly diffuse photosynthetic photon flux density
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Photosynthetic photon flux densityEcosystemSolar radiationProductivity modelsGranada (Spain)
Foyo-Moreno, I.; Alados-Arboledas, I.; Alados-Arboledas, L. A new empirical model to estimate hourly diffuse photosynthetic photon flux density. Atmospheric Research, 203: 189-196 (2018). [http://hdl.handle.net/10481/48990]
SponsorshipThis work was supported by the Andalusia Regional Government project P12-RNM-2409, by the Spanish Ministry of Economy and Competitiveness projects CGL2013-45410-R and CGL2016-81092-R, and by the European Union's Horizon 2020 research and innovation programme project ACTRIS-2 (grant agreement No 654109).
Knowledge of the photosynthetic photon flux density (Qp) is critical in different applications dealing with climate change, plant physiology, biomass production, and natural illumination in greenhouses. This is particularly true regarding its diffuse component (Qpd), which can enhance canopy light-use efficiency and thereby boost carbon uptake. Therefore, diffuse photosynthetic photon flux density is a key driving factor of ecosystem-productivity models. In this work, we propose a model to estimate this component, using a previous model to calculate Qp and furthermore divide it into its components. We have used measurements in urban Granada (southern Spain), of global solar radiation (Rs) to study relationships between the ratio Qpd/Rs with different parameters accounting for solar position, water-vapour absorption and sky conditions. The model performance has been validated with experimental measurements from sites having varied climatic conditions. The model provides acceptable results, with the mean bias error and root mean square error varying between − 0.3 and − 8.8% and between 9.6 and 20.4%, respectively.