Download presentation
Presentation is loading. Please wait.
Published byMadeleine Miller Modified over 9 years ago
1
Flux–Model–MODIS 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
2
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 km 2 vs point ° 0.5 hr vs daily –Comparison statistics: correlations?
3
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
4
Re-projecting MODIS Data Park Falls, WI UTM Integerized Sinusoidal MODIS sinusoidal
5
Harvard Forest, ISIN, all pixels in 5x5 km area: LAI, fPAR, EVI, PSN
6
Harvard Forest, ISIN, good pixels in 3x3 km area: LAI, fPAR, EVI, PSN
7
Metolius PSN product All pixels in 3x3 area Two distinct sets of PSN values, may be due to different land cover types Metolius PSN product All pixels in 3x3 area Two distinct sets of PSN values, may be due to different land cover types Heterogeneity in MODIS pixels near tower
8
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
9
MODIS Products- Walker Branch PSN fPAR LAI EVI
10
MODIS Products - Harvard Forest
13
WB Flux 1995-98 Lotec NEP 2000-01 MODIS PSN 2001 Lotec / MODIS
14
WB Flux 1995-98 BGC NEP 2000-01 MODIS PSN 2001 BGC / MODIS
15
HF Flux 1992-99 MODIS PSN 2001 Lotec NEP 2000-2001 Lotec / MODIS
16
HF Flux 1992-99 MODIS PSN 2001 BGC NEP 2000-2001 BGC / MODIS
17
Measured Relative LAI - WB Time to 50% LAI Max as Function of Average Spring Temp. Time to 50% LAI Max as Function of Degree Growing Days
19
UMBS, ISIN, good pixels in 3x3 km area: LAI, fPAR, EVI, PSN
20
Metolius, ISIN, good pixels in 3x3 km area: LAI, fPAR, EVI, PSN
21
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
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.