Biomass science goals
The mission of the Biomass satellite is to measure forest biomass from space.
Forest biomass, defined as the dry plant weight per unit area, is a key element of the carbon cycle and is made up of 50% carbon. Most aerial biomass is in forests and a majority of these are at tropical latitudes. But forest biomass is still poorly understood and therefore a major source of uncertainty when estimating carbon fluxes.
Why measure biomass globally?
The build-up of greenhouse gases is fuelling global warming. However, the biosphere acts like a sink, drawing down carbon dioxide (CO2) from the atmosphere and slowing this warming process. But the spatial distribution and extent of such sinks are unknown. To understand, curb and cope with the effects of climate change, we need to reduce the uncertainties surrounding the global carbon cycle.
To this end, we must:
- reduce uncertainties in estimating stocks and fluxes of terrestrial carbon
- define an objective baseline to be applied in international treaties (REDD+)
- constrain surface and climate models
- better monitor our planet’s resources
The space component of the mission comprises a single satellite carrying a synthetic aperture radar (SAR) operating in P band in a fixed sun-synchronous, near-polar, near-circular orbit at an altitude ranging from 637 km to 666 km, according to the phase of the mission. This orbit is designed to enable repeat acquisitions of interferometric data throughout the mission and to minimize the impact of ionospheric perturbations.
The baseline launcher chosen to orbit the Biomass satellite is Vega. The satellite is also compatible with other launchers like Antares (U.S.) and PSLV (India).
The mission has been designed to acquire measurements at dawn and dusk, i.e., a local equator-crossing time of 6:00 and 18:00, to minimize unwanted ionospheric effects on the radar signal. SAR data will be received by the Kiruna ground station over an X-band link. Metadata are necessary to quantify the characteristics of the signal’s propagation path and are used in the final data calibration and processing system.
The Biomass mission is planned to last 5 years and will comprise a short tomography phase of around 55 days, followed by the nominal operational phase, during which the satellite will have a revisit rate of 25 days.
The tomography phase will follow on immediately from the in-orbit checkout phase. Once this phase is completed, the satellite will be moved into its nominal orbit until the end of the mission, when it will be deorbited without any need for fuel due its low orbit.