Ecosystem composition is key attribute of the terrestrial biosphere, affecting its current and future carbon, water, and energy fluxes. Information on ecosystem composition has traditionally come from ground-based inventory measurements that provide detailed information on the composition and structure of the above-ground plant canopy. However, due to their limited spatial extent, ground-based inventories do not provide a comprehensive picture of ecosystem composition at regional or global scales. In this analysis we evaluate the ability of the imaging spectrometry measurements to provide spatially comprehensive estimates of canopy composition that can be used to constrain terrestrial biosphere model simulations across the heterogeneous landscapes of the Californian Sierras.
Our results show that imaging spectrometry measurements can be successfully used to estimate regional-scale variation in ecosystem composition and resulting spatial heterogeneity in patterns of carbon, water and energy fluxes and ecosystem dynamics. Simulations at four flux tower sites within the study region yields patterns of seasonal and inter-annual variation in carbon fluxes that have comparable accuracy to simulations initialized from ground-based inventory measurements. These results suggest that terrestrial biosphere model simulations can utilize modern remote-sensing data on vegetation composition to improve their predictions of the current and near-term future functioning of the terrestrial biosphere.