Prezentace aplikace PowerPoint

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ALGORITHMS FOR GLOBAL LAI/FAPAR ESTIMATION USING
VGT SATELLITE IMAGERY
Jan Pisek, Jing M. Chen, Feng Deng, Stephen
Plummer
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Spatial and temporal resolution of the product

- global coverage in 1 km spatial resolution
- global maps produced with a time-step of 10
days
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Global LAI product

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d. Direct validation A Canada
- 7 validation sites
- Pisek et al. 2006, CJRS, in review
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d. Direct validation A Canada
- 7 validation sites
Victoria 4km x 4km LAI
Ottawa 4km x 4km LAI
Kanaskasis 4km x 4km LAI
Radisson 4km x 4km LAI
TM data 1998 VGT/MODIS LAI2003
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d. Direct validation B BigFoot sites
- used 4 sites AGRO, HARV, KONZ, NOBS

• BigFoot TM scenes (http//www.fsl.orst.edu/larse/
  bigfoot/)

• MODIS ASCII subsets (http//www.modis.ornl.gov/mo
  dis/index.cfm)

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b. Specifics of the algorithm
- BRDF effects are incorporated into LAI
algorithms

• LAI algorithms are developed separately for
• several structurally distinct land cover types

- spectral indices related to the effective LAI
- all living organisms included in LAI before
sound background values can be acquired

• both SR-based algorithms and the RSR-based
• algorithms are being used

• algorithms were developed using Landsat ETM
• spectral bands

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c. Missing data / data quality
- downloaded VGT data already atmospherically
corrected by the Simplified Method for
Atmospheric Correction (SMAC) (Rahman and
Didieu, 1994)
- we further apply a procedure called Locally
Adjusted Cubic-spline Capping (LACC) (Chen et
al., 2006, IEEE)
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c. Missing data / data quality LACC smoothing
(Chen et al., 2006, IEEE)
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f. Multi-sensor fusion and synergy

converting effective LAI to LAI
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g. Future product
- development of global fields of clumping index
and background reflectances using MISR and
POLDER sensor data

• algorithms overview Deng et al., IEEE, 2006
• validation over Canada Pisek et al., CJRS,
• in review
• validation over BigFoot sites Pisek Chen,
• Missoula poster