IEEE Proof IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING, VOL. 44, NO. 7, JULY 2006 1 Validation of Global Moderate-Resolution LAI Products: A Framework Proposed Within the CEOS Land Product Validation Subgroup Jeffrey T. Morisette, Frèdéric Baret, Jeffrey L. Privette, Ranga B. Myneni, Jaime Nickeson, Sébastien Garrigues, Nikolay Shabanov, Marie Weiss, Richard Fernandes, Sylvain Leblanc, Margaret Kalacska, G. Arturo Sánchez-Azofeifa, Michael Chubey, Benoit Rivard, Pauline Stenberg, MiinaRautiainen, Pekka Voipio, Terhikki Manninen, Andrew N. Pilant, Timothy E. Lewis, John S. Iiames, Roberto Colombo, Michele Meroni, Lorenzo Busetto, Warren Cohen, David P. Turner, Eric D. Warner, G. W. Petersen, Guenter Seufert, and Robert Cook Abstract—Initiated in 1984, the Committee Earth Observing Satellites’ Working Group on Calibration and Validation (CEOS WGCV) pursues activities to coordinate, standardize and advance calibration and validation of civilian satellites and their data. One subgroup of CEOS WGCV, Land Product Validation (LPV), was established in 2000 to define standard validation guidelines Manuscript received February 4, 2005; revised May 26, 2006. This work was supported in part by the National Aeronautics and Space Adminsitration under Grants EOS/03-0408-0637 and NNG04GK24G, in part by the Academy of Fin- land under Grant 47615, and in part by the Technology Development Centre (TEKES) of Finland under Grant AO423. J. T. Morisette and J. L. Privette are with the NASA Goddard Space Flight Center, Greenbelt, MD 20771 USA (e-mail: jeff.morisette@nasa.gov). F. Baret, S. Garrigues, and M. Weiss are with the Institut Scientifique de Recherche Agronomique Climat Sol et Environnement (INRA-CSE) Agroparc, 84914 Avignon, France. R. B. Myneni and N. Shabanov are with Boston University, Boston, MA 02215 USA. J. Nickeson is with Science Systems and Applications, Incorporated, Lanham, MD 20706 USA. R. Fernandes and S. Leblanc are with the Canda Centre for Remote Sensing, Ottawa, ON K1A 0Y7, Canada. M. Kalacska, G. A. Sánchez-Azofeifa, M. Chubey, and B. Rivard are with the Earth Observation Systems Laboratory (EOSL), Earth and Atmospheric Sci- ences Department, University of Alberta, Edmonton, AB T6G 2E3, Canada. P. Stenberg and M. Rautiainen are with the Department of Forest Ecology, University of Helsinki, FIN-00014 Helsinki, Finland. P. Voipio is with the Finnish Forest Research Institute, Suonenjoki Research Station, FIN-77600 Suonenjoki, Finland. T. Manninen is with the Finnish Meteorological Institute, Research and De- velopment, Earth Observation, au: postal code and city? Finland. A. N. Pilant, T. E. Lewis, and J. S. Iiames are with the U.S. Environmental Protection Agency, Research Triangle Park, NC 27711 USA. R. Colombo and L. Busetto are with the Dipartimento di Scienze dell’Am- biente e del Territorio, Laboratorio Telerilevamento, Università Milano-Bic- occa, 20126 Milano, Italy. M. Meroni is also with the UNITUS-DISAFRI, Lab. Ecologia Forestale, Università della Tuscia, 01100 Viterbo, Italy. M. Meroni is with the Dipartimento di Scienze dell’Ambiente e del Territorio, Laboratorio Telerilevamento, Università Milano-Bicocca, 20126 Milano, Italy, and also with the Dipartimento di Scienze dell’Ambiente Forestale e delle sue Risorse, Laboratorio Ecologia Forestale, Università della Tuscia, 01100 Viterbo, Italy. W. Cohen is with the Corvallis Forestry Sciences Laboratory, U.S. Depart- ment of Agriculture Forest Service, Corvallis, OR 97331 USA. D. P. Turner is with the Oregon State University, Corvallis OR 97331 USA. E. D. Warner and G. W. Petersen are with Pennsylvania State University, Uni- versity Park, PA 16802 USA. G. Seufert is with the Joint Reserach Center Institute for Environment and Sustainability, Climate Change Unit, 21–20 Ispra (VA), Italy. R. Cook is with the Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge TN 37831 USA. Digital Object Identifier 10.1109/TGRS.2006.872529 and protocols and to foster data and information exchange rel- evant to the validation of land products. Since then, a number of leaf area index (LAI) products have become available to the science community at both global and regional extents. Having multiple global LAI products and multiple, disparate validation activities related to these products presents the opportunity to realize efficiency through international collaboration. So the LPV subgroup established an international LAI intercomparison validation activity. This paper describes the main components of this international validation effort. The paper documents the current participants, their ground LAI measurements and scaling techniques, and the metadata and infrastructure established to share data. The paper concludes by describing plans for sharing both field data and high-resolution LAI products from each site and the LPV group’s plans to synthesize the data and site-specific results into a global intercomparison. Many considerations of this global LAI intercomparison can apply to other products, and this paper presents a framework for such collaboration. Index Terms—Author, please supply your own keywords or send a blank e-mail to keywords@ieee.org to receive a list of suggested keywords. I. BACKGROUND A. Committee on Earth Observing Satellite’s Land Product Validation Subgroup T HE Committee Earth Observing Satellites’ Working Group on Calibration and Validation (CEOS WGCV) was initiated in 1984 to pursue activities to coordinate, standardize, and advance calibration and validation of civilian Earth-ob- serving satellites and their data. Five subgroups comprise the implementation arm of the WGCV. One subgroup, Land Product Validation (LPV) [72], was established in 2000 to define standard guidelines and protocols, and to foster data and information exchange relevant to the validation of land products. The subgroup’s emphasis since its inception has been to provide a validation service for the Global Terrestrial Observation System (GTOS) [73]. This implies a focus on the terrestrial “Essential Climate Variables” of GTOS; which lists a number of critical products including leaf area index (LAI) [1]. Global LAI products provide key information on the exchange of energy, mass (e.g., water and CO2), and momentum flux between Earth’s surface and the atmosphere. LAI is utilized in most ecosystem productivity models and global models 0196-2892/$20.00 © 2006 IEEE