Expanding global mapping of the foliage clumping index with multi-angular POLDER three measurements: Evaluation and topographic compensation |
| |
| Authors: | Jan Pisek Jing M. Chen Roselyne Lacaze Oliver Sonnentag Krista Alikas |
| |
| Affiliation: | 1. Department of Geographical Sciences, University of Maryland, College Park, MD 20742, USA;2. NASA-Goddard Space Flight Center, Greenbelt, MD 20771, USA;3. EMMAH, INRA-UMR 1114, Domaine Saint-Paul, Site Agroparc, 84914 Avignon, France;4. CESBIO, UMR CNES-CNRS-IRD-UPS, 18, avenue Edouard Belin, 31401 Toulouse Cedex 4, France;1. State Key Laboratory of Remote Sensing Science, Jointly Sponsored by Beijing Normal University and Institute of Remote Sensing and Digital Earth of Chinese Academy of Sciences, Beijing Engineering Research Center for Global Land Remote Sensing Products, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China;2. Centre d''Etudes Spatiales de la Biosphere, Toulouse, France;3. Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, USA;4. Singapore-MIT Alliance for Research and Technology, 1 Create Way, 138602, Singapore;1. EOLAB, Parc Científic Universitat de València, c/ Catedràtic José Beltrán, 2. 46980 Paterna, Valencia, Spain;2. HYGEOS, Euratechnologies, 165 avenue de Bretagne, 59000 Lille, France;3. INRA, UAPV, UMR1114 EMMAH, Domaine Saint-Paul, Site Agroparc, 84914 Avignon, France;1. State Key Laboratory of Remote Sensing Science, Jointly Sponsored by Beijing Normal University and the Institute of Remote Sensing and Digital Earth of Chinese Academy of Sciences, Beijing 100875, China;2. Beijing Engineering Research Center for Global Land Remote Sensing Products, Institute of Remote Sensing Science and Engineering, Faculty of Geographical Science, Beijing Normal University, Beijing 100875;3. Laboratoire des Sciences du Climat et de l''Environnement, CEA-CNRS-UVSQ, 91191 Gif sur Yvette, France;4. School for the Environment, University of Massachusetts Boston, Boston, MA, USA;5. Terrestrial Information Systems Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA;6. Earth System Science Interdisciplinary Center, University of Maryland College Park, MD, USA |
| |
| Abstract: | The clumping index measures the spatial aggregation (clumped, random and regular) of foliage elements. The global mapping of the clumping index with a limited eight-month multi-angular POLDER 1 dataset is expanded by integrating new, complete year-round observations from POLDER 3. We show that terrain-induced shadows can enhance bi-directional reflectance distribution function variation and negatively bias the clumping index (i.e. indicating more vegetation clumping) in rugged terrain. Using a global high-resolution digital elevation model, a topographic compensation function is devised to correct for this terrain effect. The clumping index reductions can reach up to 30% from the topographically non-compensated values, depending on terrain complexity and land cover type. The new global clumping index map is compared with an assembled set of field measurements from 32 different sites, covering four continents and diverse biomes. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
