DEVELOPMENT OF A COUPLED LEAF AND CANOPY MODEL FOR THE SIMULATION OF PLANT-ATMOSPHERE INTERACTION

A numerical scheme was developed to couple a multilayer canopy radiati on model, a photosynthesis model for C-3 species, and a leaf stomatal conductance model with a single leaf energy balance equation. This cou pled leaf and canopy model was used to simulate the responses of a hor izontally uniform forest canopy to its ambient microenvironment, using micrometeorological data collected from field measurements in a fores t canopy. Emphasis was placed on issues associated with modeling the t ransient responses of plant leaves. For example, thermal storage was f ound to be important in modeling transience of leaf temperature, which in turn influenced the transient heating or cooling of the atmosphere by plant leaves. In addition, modification of the Ball-Berry leaf sto matal conductance model, using an exponential formula with an empirica l time lag, yielded more realistic transient leaf stomatal conductance s, which were important for estimating evaporation and CO2 assimilatio n.