Abstract
Global maps of land cover and leaf area index (LAI) derived from the Moderate Resolution Imaging Spectrometer (MODIS) reflectance data are an important resource in studies of global change, but errors in these must be characterized and well understood. Product validation requires careful scaling from ground and related measurements to a grain commensurate with MODIS products. We present an updated BigFoot project protocol for developing 25-m validation data layers over 49-km2 study areas. Results from comparisons of MODIS and BigFoot land cover and LAI products at nine contrasting sites are reported. In terms of proportional coverage, MODIS and BigFoot land cover were in close agreement at six sites. The largest differences were at low tree cover evergreen needleleaf sites and at an Arctic tundra site where the MODIS product overestimated woody cover proportions. At low leaf biomass sites there was reasonable agreement between MODIS and BigFoot LAI products, but there was not a particular MODIS LAI algorithm pathway that consistently compared most favorably. At high leaf biomass sites, MODIS LAI was generally overpredicted by a significant amount. For evergreen needleleaf sites, LAI seasonally was exaggerated by MODIS. Our results suggest incremental improvement from Collection 3 to Collection 4 MODIS products, with some remaining problems that need to be addressed.
Original language | English |
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Article number | 1645284 |
Pages (from-to) | 1843-1857 |
Number of pages | 15 |
Journal | IEEE Transactions on Geoscience and Remote Sensing |
Volume | 44 |
Issue number | 7 |
DOIs | |
State | Published - Jul 2006 |
Funding
Manuscript received October 15, 2004; revised January 16, 2006. This work was supported by the National Aeronautics and Space Administration under the Terrestrial Ecology Program. W. B. Cohen and R. E. Kennedy are with the Forestry Sciences Laboratory, Pacific Northwest Research Station, U.S. Department of Agriculture Forest Service, Corvallis, OR 97331 USA (e-mail: [email protected]). T. K. Maiersperger, D. P. Turner, W. D. Ritts, D. Pflugmacher, and A. Kirschbaum are with the Department of Forest Science, Forestry Sciences Laboratory, Oregon State University, Corvallis, OR 97331 USA. S. W. Running is with the School of Forestry, University of Montana, Missoula, MT 59812 USA. M. Costa is with the Universidade Federal de Viçosa, Viçosa MG 36570-000, Brazil. S. T. Gower is with the Department of Forest Ecology and Management, University of Wisconsin, Madison, WI 53706 USA. Digital Object Identifier 10.1109/TGRS.2006.876026
Funders | Funder number |
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National Aeronautics and Space Administration |
Keywords
- Land cover
- Landsat
- Leaf area index (lai)
- Moderate resolution imaging spectrometer (modis)
- Scaling
- Validation