Interactions Between Plant Canopy Structure and Probability Distributions of Absorbed Radiative Fluxes, Photosynthetic Fluxes, and Water-Use Efficiency

Plant canopy structure (e.g., leaf angle distribution, leaf area distribution, heterogeneity) mediates the distribution of absorbed radiative fluxes, which drives critical sub-processes such as the energy balance, transpiration fluxes, and photosynthesis. Most commonly, interactions between canopy structure and radiative fluxes are viewed in an integral sense, where radiative fluxes are described based on averages over a given volume of leaves. This level of aggregation obscures important details of how canopy structure affects the distribution of leaf-level radiative fluxes across the canopy, and in turn its effect on the distribution of sub-processes such as photosynthesis. This work will use a leaf-resolving three-dimensional biophysical model, Helios, to explore how the canopy leaf angle distribution, leaf area distribution, and vegetation heterogeneity influences the probability distribution of absorbed radiative fluxes at the leaf-level. The model will also be used to simulate sub-leaf-level fluxes of CO₂ and water vapor in order to link the probability distributions of absorbed radiative fluxes to probability distributions of photosynthetic fluxes and water-use efficiency.