Retrieval of forest architecture from POLDER hot spot measurements to assess clumping indices and LAI at various scales

The complex structure of conifer species affects the radiation scattering processes and influences the shape of the bidirectional reflectance distribution function (BRDF). An interesting signature is the hot spot phenomenon which is sensitive to the foliage architecture. The GHOST (G and HOt SpoT) model simulates the directional reflectance by reproducing the hot spot peak and taking into account the canopy architecture through the expression of the G-function. The model is inverted against POLDER data acquired at various spatial resolutions over boreal forest. The inversion method, based upon the angular domain of predominant influence of each parameter, yields the structural characteristics of the stem distribution on the patch scale