The Role of Spatial Averaging Scale in Leaf‐To‐Canopy Scaling of Non‐Linear Processes in Homogeneous Canopies

Abstract

Introduction Problem Statement and ObjectivesNon-linear processes including photosynthesis and stomatal conductance are typically measured and modeled at the leaf level and must be integrated or up-scaled in order to compute canopy level fluxes. Common spatial scaling methods are based on a grouping of similar leaves (or leaf area), modeling a representative (average) leaf from each group, and multiplying the result by the total canopy leaf area in each group. Models are applied across the entire group to yield average values or fluxes. A complication arises when multiple sub-models are coupled together based on these average input values if the processes are non-linear. For example, the response of photosynthesis to light is non-linear (Rabinowitch, 1951), which means that inputting the average light flux into a photosynthesis model does not necessarily lead to the correct