1Max Planck Institute for Biogeochemistry, 07745 Jena, Germany
2Natural Resources Ecology Lab, Colorado State University, Fort Collins, USA
3CEFE-CNRS, 34293 Montpellier cedex 5, France
4Department of Forest Science and Environment, University of Tuscia, 01100 Viterbo, Italy
5Department of Geography, Indiana University, Bloomington, Indiana, USA
6Friedrich-Schiller-University Jena, 07743 Jena, Germany
Received: 20 Aug 2010 – Published in Biogeosciences Discuss.: 14 Sep 2010
Abstract. Several studies sustained the possibility that a photochemical reflectance index (PRI) directly obtained from satellite data can be used as a proxy for ecosystem light use efficiency (LUE) in diagnostic models of gross primary productivity. This modelling approach would avoid the complications that are involved in using meteorological data as constraints for a fixed maximum LUE. However, no unifying model predicting LUE across climate zones and time based on MODIS PRI has been published to date. In this study, we evaluate the effectiveness with which MODIS-based PRI can be used to estimate ecosystem light use efficiency at study sites of different plant functional types and vegetation densities. Our objective is to examine if known limitations such as dependence on viewing and illumination geometry can be overcome and a single PRI-based model of LUE (i.e. based on the same reference band) can be applied under a wide range of conditions. Furthermore, we were interested in the effect of using different faPAR (fraction of absorbed photosynthetically active radiation) products on the in-situ LUE used as ground truth and thus on the whole evaluation exercise. We found that estimating LUE at site-level based on PRI reduces uncertainty compared to the approaches relying on a maximum LUE reduced by minimum temperature and vapour pressure deficit. Despite the advantages of using PRI to estimate LUE at site-level, we could not establish an universally applicable light use efficiency model based on MODIS PRI. Models that were optimised for a pool of data from several sites did not perform well.
Revised: 11 Jan 2011 – Accepted: 11 Jan 2011 – Published: 26 Jan 2011
Goerner, A., Reichstein, M., Tomelleri, E., Hanan, N., Rambal, S., Papale, D., Dragoni, D., and Schmullius, C.: Remote sensing of ecosystem light use efficiency with MODIS-based PRI, Biogeosciences, 8, 189-202, doi:10.5194/bg-8-189-2011, 2011.