Flux–Model–MODIS Evaluation
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Flux–Model–MODIS Flux–Model–MODIS Evaluation Evaluation Dick Olson, Tom Boden, Bob Cook, Lisa Olsen, Steve Margle, many others Oak Ridge National Laboratory* Oak Ridge, Tennessee, USA *Managed by the University of Tennessee-Battelle LLC under contract DE-AC05-00OR22725 with the U.S. Department of Energy. EMDI 3 Working Group April 2002
description
Flux–Model–MODIS Evaluation. EMDI 3 Working Group April 2002. Dick Olson, Tom Boden, Bob Cook, Lisa Olsen, Steve Margle, many others Oak Ridge National Laboratory* Oak Ridge, Tennessee, USA. *Managed by the University of Tennessee-Battelle LLC - PowerPoint PPT Presentation
Transcript of Flux–Model–MODIS Evaluation
Flux–Model–MODISFlux–Model–MODISEvaluationEvaluation
Dick Olson, Tom Boden,Bob Cook, Lisa Olsen,
Steve Margle, many othersOak Ridge National Laboratory*
Oak Ridge, Tennessee, USA
*Managed by the University of Tennessee-Battelle LLC under contract DE-AC05-00OR22725 with the U.S. Department of Energy.
EMDI 3 Working GroupApril 2002
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Components NEE – eddy covariance flux towers NPP – ecosystem field measurements MODIS – EOS Validation program Modeled NPP – ad hoc participation EMDI 3 Prototype exercise:
– 3 sites (history of timely data processing)° Harvard Forest – Bill Monger° UMBS – Peter Curtis° Metolius – Bev Law
– Scaling issues: ° NEE vs NPP° >1 km2 vs point° 0.5 hr vs daily
– Comparison statistics: correlations?
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Flux-Model-MODIS Comparison
Fluxes: 17 towers – Micrometeorology posted near real-time
– Gap-filled flux estimates posted annually Models: 5 models participating (open to others)
– Common site characteristics–model driver data MODIS: 7 products for 52 sites (8-day composites)
– Surface Temperature, Vegetation Index, LAI, fPAR, Photosynthesis (8-day and annual), Surface Reflectance, BRDF
– Sites include Core Validation Sites, Flux Tower Sites, BigFoot Sites, Real Time Validation activity, and LAINet Sites
Format is 7 km x 7 km cutouts in ISIN projection in ASCII files
Re-projecting MODIS DataPark Falls, WI
UTMUTMIntegerized SinusoidalIntegerized Sinusoidal
MODIS sinusoidalMODIS sinusoidal
Harvard Forest, ISIN, all pixels in 5x5 km area: LAI, fPAR, EVI, PSN
Harvard Forest, ISIN, good pixels in 3x3 km area: LAI, fPAR, EVI, PSN
Metolius •PSN product•All pixels in 3x3 area Two distinct setsof PSN values, may bedue to different land cover types
Metolius •PSN product•All pixels in 3x3 area Two distinct setsof PSN values, may bedue to different land cover types
Heterogeneity in MODIS
pixels near tower
Walker Branch•Pixels with LAI and PSN•All pixels in 5x5km area• MODIS landcover: broadleaf crops (8 pixels) broadleaf forest (8 pixels) needleleaf forest (9 pixels)
No differences between types, may be due to mixed pixels
Walker Branch•Pixels with LAI and PSN•All pixels in 5x5km area• MODIS landcover: broadleaf crops (8 pixels) broadleaf forest (8 pixels) needleleaf forest (9 pixels)
No differences between types, may be due to mixed pixels
Lack of Heterogeneity
in MODIS pixels near tower
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MODIS Products- Walker Branch
PSN
fPAR
LAIEVI
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MODIS Products - Harvard Forest
WB Flux 1995-98
Lotec NEP 2000-01
MODIS PSN 2001
Lotec / MODIS
WB Flux 1995-98
BGC NEP 2000-01
MODIS PSN 2001
BGC / MODIS
HF Flux 1992-99
MODIS PSN 2001
Lotec NEP 2000-2001
Lotec / MODIS
HF Flux 1992-99
MODIS PSN 2001
BGC NEP 2000-2001
BGC / MODIS
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Measured Relative LAI - WB
Time to 50% LAIMax as Function of
Average Spring Temp.
Time to 50% LAIMax as Function of
Degree GrowingDays
UMBS, ISIN, good pixels in 3x3 km area: LAI, fPAR, EVI, PSN
Metolius, ISIN, good pixels in 3x3 km area: LAI, fPAR, EVI, PSN
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Comparison of Flux-Model-MODIS
Walker Branch– MODIS LAI compares favorably to 10-yrs LAI field
measurements– Springtime pattern is about the same
° Lotec is later
° MODIS PSN is earlier
– Lotec model NEP is about half measured NEE
Harvard Forest– Springtime pattern is about the same
° Lotec is later
° MODIS PSN is earlier
– Lotec model NEP is about same as measured NEE
