MODELING THE CLEAR-SKY SURFACE-ENERGY BUDGET DURING FIFE 1987

A canopy level soil-vegetation-atmosphere transfer model (land ecosyst em-atmosphere feedback (LEAF) model is used to simulate components of the daily surface energy budget. The Sellers et al. (1992b) model is u sed to relate unstressed canopy conductance to the fraction of the inc ident photosynthetically active radiation absorbed by the canopy and t he simple ratio vegetation index. The multivariate randomized block pe rmutation (MRBP) procedure is used to obtain values for a number of pa rameters used in environmental stress functions and the aerodynamic re sistances. It is shown that the MRBP procedure was able to improve the LEAF model predictions for three responses (i.e., net radiation, sens ible, and latent heat fluxes). When comparing model predictions to the observations for the four intensive field campaigns of the First Inte rnational Satellite Land Surface Climatology Project Field Experiment, the model performance is reasonably good. The difference in the param eterization of canopy conductance between the Sellers et al. (1992b) m odel and the LEAF model is discussed.