B53C-0206:
Light use efficiency of terrestrial vegetation from remote sensing of chlorophyll fluorescence
Friday, 19 December 2014
Grayson M Badgley1, Kaiyu Guan1, Joe A Berry2, David B Lobell3 and Youngryel Ryu4, (1)Stanford University, Stanford, CA, United States, (2)Carnegie Institution for Science, Global Ecology, Washington, DC, United States, (3)Stanford University, Los Altos Hills, CA, United States, (4)Seoul National University, Department of Landscape Architecture and Rural Systems Engineering, Seoul, South Korea
Abstract:
Light use efficiency, the rate with which plants use absorbed photons to fix carbon dioxide, is a crucial parameter for estimating terrestrial carbon fluxes. Estimates of light use efficiency lie at the heart of how we model and understand ecosystem productivity. Here, we make use of the recent availability of high-resolution, multi-year records of remotely sensed measurements of chlorophyll fluorescence to refine estimates of light use efficiency in terrestrial ecosystems at the global scale. Directly estimating light use efficiency from remote sensing can help guide the current approach of constraining a theoretical maximum light use efficiency using meteorological data. We explore the usefulness of a derived light use efficiency at the global scale from remotely sensed records of chlorophyll fluorescence, photosynthetically active radiation, and canopy leaf area. Our estimates of light use efficiency show good agreement with light use efficiency calculated using Fluxtower data spanning several continents and a wide variety of ecosystems. We further benchmark our approach against the light use efficiency estimated from a variety of ecosystem models, such as BESS. Further refinement of our proposed technique promises to advance our ability to detect ecosystem stresses and further constrain our estimates of carbon fluxes within terrestrial ecosystems.
