ESTIMATING SPARSE FOREST RAINFALL INTERCEPTION WITH AN ANALYTICAL MODEL

Gash's analytical model of rainfall interception is reformulated, with improved boundary conditions, to give a better description of the eva poration from sparse forest. The model is tested against data from Les Landes Forest collected during HAPEX-MOBILHY. The new formulation req uires an estimate of the evaporation per unit area of canopy, rather t han per unit ground area. When the evaporation per unit area of canopy is equated with the estimates of evaporation derived from the Penman- Monteith equation there is an improved description of the observations .