Biomass report - A contribution to the scientif case for the P-Band BIOMASS Mission Proposal

This report has been produced on behalf of the European Space Agency as part of the study “Assessing the Use of BIOMASS Mission Information within Global Vegetation and Carbon Models”, ESTEC Contract No. 20989/07/NL/CB. It reflects the substantial interest of the European and international climate and global change research communities in the potential of a future spatially resolved, consistent global data set of space-based biomass measurements for monitoring, simulation and prediction. The interim report has highlighted the importance of the vegetation biomass to the global carbon cycle. The present report is structured in two different sections that describe 1) how biomass can be estimated from different data products and 2) how biomass can be modelled at a global scale. The ground data part demonstrates different approaches for estimating biomass and examines the relationship between height and biomass as well as the influence of stand age on biomass. The modelling part gives an overview on how height and biomass are estimated in global vegetation models and how other modelled parameters and processes such as evapotranspiration are influenced by the accuracy of biomass estimates. Woody biomass is altered by human intervention through land use change and forest management. These disturbances lead to major destruction and withdrawal of forest biomass. Vegetation models can significantly benefit from measured data about the type, structure and biomass of vegetation, and therefore BIOMASS could contribute to validate model results and as a result improve the model representation of the processes that underlie biomass stocks and dynamics. In addition, from the site data different allometric functions can be derived so as to provide spatially explicit data for calibration and validation for BIOMASS.