Summary:

Flow Diagram of Leaf Flux Calculations

The article describes the flow diagram of leaf flux calculations in the PHS (Photosynthesis-Hydrology-Stomatal) scheme, which is nested within the loop that solves for sensible and latent heat fluxes and temperature for vegetated surfaces.

The PHS scheme iterates for convergence of leaf temperature (Tl), transpiration water stress (βt), and intercellular CO2 concentration (ci). The scheme first solves for assimilation, stomatal conductance, and intercellular CO2 with βt,sun and βt,shade both set to 1, to determine the maximum transpiration rates (Esun,max and Eshade,max).

Next, using the maximum transpiration rates, the scheme solves for Ψ, βt,sun, and βt,shade. These values for βt,sun and βt,shade are then used in the photosynthesis routine, which solves for attenuated photosynthesis and stomatal conductance, reflecting the water stress. This again involves iterating to convergence of ci.

The outermost level of iteration works towards convergence of leaf temperature, reflecting the leaf surface energy balance.

The article includes a flow diagram (Figure 2.11.2) that visually represents the iterative process described in the text.