The purpose of the Tropisar campaign, carried out by Onera in collaboration with Cesbio and the Toulouse laboratory" Evolution and Biological Diversity" on behalf of the ESA and CNES, is to conduct a series of measurement operations using radardata for the forests of Guyana... Once the radardata acquired by Sethi* has been processed, the Onera scientists will compare the biomass data obtained by the airborne method with what they already have in order to evaluate the precision of the system of remote sensing of forest biomass, planned for the Biomass project