Abstract
The Moderate Resolution Spectroradiometer (MODIS) sensor has provided near real-time estimates of gross primary production (GPP) since March 2000. We compare four years (2000 to 2003) of satellite-based calculations of GPP with tower eddy CO 2 flux-based estimates across diverse land cover types and climate regimes. We examine the potential error contributions from meteorology, leaf area index (LAI)fPAR, and land cover. The error between annual GPP computed from NASA's Data Assimilation Office's (DAO) and tower-based meteorology is 28%, indicating that NASA's DAO global meteorology plays an important role in the accuracy of the GPP algorithm. Approximately 62% of MOD15-based estimates of LAI were within the estimates based on field optical measurements, although remaining values overestimated site values. Land cover presented the fewest errors, with most errors within the forest classes, reducing potential error. Tower-based and MODIS estimates of annual GPP compare favorably for most biomes, although MODIS GPP overestimates tower-based calculations by 20%-30%. Seasonally, summer estimates of MODIS GPP are closest to tower data, and spring estimates are the worst, most likely the result of the relatively rapid onset of leaf-out. The results of this study indicate, however, that the current MODIS GPP algorithm shows reasonable spatial patterns and temporal variability across a diverse range of biomes and climate regimes. So, while continued efforts are needed to isolate particular problems in specific biomes, we are optimistic about the general quality of these data, and continuation of the MOD17 GPP product will likely provide a key component of global terrestrial ecosystem analysis, providing continuous weekly measurements of global vegetation production.
Original language | English (US) |
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Article number | 1645290 |
Pages (from-to) | 1908-1923 |
Number of pages | 16 |
Journal | IEEE Transactions on Geoscience and Remote Sensing |
Volume | 44 |
Issue number | 7 |
DOIs | |
State | Published - Jul 2006 |
Bibliographical note
Funding Information:Manuscript received October 1, 2004; revised April 25, 2005. This work was supported in part by the U.S. National Aeronautics and Space Administration (NASA) Earth Science Enterprise under MODIS Contract NAS5-31368. Eddy covariance flux tower sites are part of both the AmeriFlux and Fluxnet networks and are funded through a number of agencies, including the Department of Energy (DOE), the National Institute for Global Environmental Change (NIGEC), and NASA. F. A. Heinsch, M. Zhao, S. W. Running, and J. S. Kimball are with The University of Montana, Missoula, MT 59812 USA (e-mail: faithann@ ntsg.umt.edu). R. R. Nemani was with The University of Montana, Missoula, MT 59812 USA. He is now with NASA’s Ames Research Center, Moffett Field, CA 94035 USA. K. J. Davis, A. R. Desai, and D. M. Ricciuto are with The Pennsylvania State University, State College, PA 16804 USA. P. V. Bolstad and B. D. Cook are with the University of Minnesota, St. Paul, MN 55108 USA. B. E. Law is with Oregon State University, Corvallis, OR 97331 USA. W. C. Oechel and H. Luo are with San Diego State University, San Diego, CA 92182 USA. H. Kwon was with San Diego State University, San Diego, CA 92182 USA. She is now with The University of Wyoming, Laramie, WY 82071 USA. S. C. Wofsy, A. L. Dunn, and J. W. Munger are with Harvard University, Cambridge, MA 02138 USA. D. D. Baldocchi is with the University of California at Berkeley, Berkeley, CA 94720 USA. L. Xu was with the University of California at Berkeley, Berkeley, CA 94720 USA. He is now with LI-COR Biosciences, Lincoln, NE 68504 USA. D. Y. Hollinger is with the USDA Forest Service Northeast Research Station, Durham, NH 03824 USA. A. D. Richardson is with the University of New Hampshire, Durham, NH 03824. P. C. Stoy and M. B. S. Siqueira are with Duke University, Durham, NC 27708 USA. R. K. Monson and S. P. Burns are with the University of Colorado, Boulder, CO 80309 USA. L. B. Flanagan is with the University of Lethbridge, Lethbridge, AB T1K 3M4 Canada. Digital Object Identifier 10.1109/TGRS.2005.853936
Keywords
- AmeriFlux
- CO eddy covariance flux [net ecosystem exchange (NEE)]
- Gross primary production (GPP)
- Moderate Resolution Imaging Spectroradiometer (MODIS)
- Remote sensing
- Terra