Forest radiative transfer models: which approach for which application?

Abstract

Radiation is fundamental in forest ecosystem ecology as it drives plant photosynthesis, morphogenesis, and fluxes of carbon, water, and energy between soil, vegetation, and the atmosphere. Though all approaches of forest radiative transfer models (FRTM) share general properties, they differ greatly in terms of calibration parameters, required assumptions, and model objectives. They use different precision levels of canopy description (from one to three dimensions) and different mathematical relationships to model the attenuation of radiation through the canopy. To date, no general guideline has been given to help the modeler choose the approach that best suits his needs. We therefore reviewed evaluation, sensitivity, and performance of FRTMs recently reported in the literature. We quantified FRTM uncertainty and identified the most sensitive parameters relative to the modeling choices. Their advantages and drawbacks are discussed, and recommendations are made relative to application potential.