Evaluation of ERS data for biomass estimation of meadows

The knowledge about the amount of biomass is necessary to determine the impact of the landcover on the hydrological cycle due to the fact that different plants show significant differences in evapotranspiration. The study area of this work is the catchment of the Ammer River, which covers about 800 km(2) in the Bavarian Alpine Foreland. Since grassland in various forms is the dominating agricultural landuse in the testsite investigations were made on the utilisation of radar data for the determination of the temporal development of grassland. ERS data were used for this task. For verification data from several meadows which were investigated from 1992-1994 are used. The plant parameters height, wet and dry biomass were measured on a weekly base during the vegetation period. Statistical approaches were applied to investigate whether one of the plant parameters can be correlated to the backscatter signal. It is shown that there is a correlation between the signal density and the vegetation height of meadows. Due to the fact that the plant height correlates with the biomass, the grassland biomass can be estimated.