Measuring Forests

Mapping forests from space

Measuring the biomass of a tree is not an easy task: unless it is cut and then weighted, its mass can only be inferred indirectly from measurements. In classical forestry, this problem can be solved for instance by measuring the height, diameter of the trunk, wood density and then calculating the mass through allometry. However, in-situ measurements are usually costly and difficult to do in remote areas and thus limited in time and space.

Thanks to the long wavelength of P-band, BIOMASS signal, depending on polarisation, will penetrate through the whole forest layer and scatter back from the bone of the tree (trunk, branches). In this way, information about forest structure can be inferred from space on a global scale.

Compared to previous spaceborne SARs, BIOMASS is the first to offer polarimetry (PolSAR), polarimetric-interferometry (PolInSAR) and tomography (TomoSAR) altogether. Interferometric observations allow for the cancellation of the ground contribution from the signal, giving measurements more correlated to the volume of biomass in the tree. The combination of interferometry and polarimetry is used for the retrieval of forest height, while tomography allows mapping forests in 3D.

In addition, the BIOMASS mission will offer the opportunity to pursue secondary objectives such as the retrieval of sub-canopy Digital Terrain Model (DTM), mapping subsurface geology (theoretically possible in deserts and glaciers), measuring ice-sheets velocity and ionosphere properties.

BIOMASS signal Illustration of BIOMASS observation modes.

Last modified April 23, 2021: [ENH] finalized navbar (c4067ca)