Drew Pilant, Ph.D.

1
EPA MODIS LAI Evaluation Activities in the
Albemarle-Pamlico Basin, NC/VA

• Drew Pilant, Ph.D.
• Timothy Lewis, Ph.D., John Iiames, Mark Murphy
  (US EPA)
• Jayantha Ediriwickrema, Ph.D. (Computer Sciences
  Corporation)
• MODIS Vegetation Workshop II, Missoula MT
• August 16, 2004

2
Outline

• EPA LAI project at a glance
• Applications of MODIS LAI at EPA
• Describe field studies
• Results and observations
• Data sets for archiving

3
LAI Project at a Glance
4
Potential Applications of MODIS LAI (MOD15A2) at
US EPA

• Biogenic emissions models (BEIS2)
• Air quality models (CMAQ)
• Atmospheric deposition models
• Landscape characterization and monitoring
• Vegetation phenology in land cover mapping and
  change detection

5
LAI Field Studies
Iiames, J.S., A.N. Pilant, T.E. Lewis. 2004.
In-situ estimates of forest LAI for MODIS data
validation. in Lunetta, R. and J. Lyon (eds.),
Remote Sensing and GIS Accuracy Assessment, CRC
Press, Boca Raton, FL.
6
Study Area Albemarle-Pamlico Basin, NC/VA
EPA Research Lab At Research Triangle Park, NC
7
Hemiphoto Optical Measurements of In Situ LAI
Hemispherical photography Upward
looking Dawn/dusk/overcast days
8
TRAC Optical Measurements of In Situ LAI
Sunfleck profiling TRAC (Tracing Radiation and
Architecture of Canopies) Full sun/mid-day
9
Real time differential GPS geolocation for
grids/transects
10
Baseline Forest Biometrics
Species distributions
Tube densiometer
Photo time series 0o 45o
Grid stake
11
Field LAI Sampling Grids and Transects
100 m
100 m
12
Scaling Field Transects to Landsat ETM
Landsat ETM image 30 m pixels
Quadrants and subplots inside hypothetical 1 km
MODIS LAI pixel
13
LAI Scaling Field to MODIS
14
Results and Observations

• LAI phenology shows green-up
• Understory removal effects on NDVI
• MODIS NDVI in LAI backup algorithm
• Field data MODIS LAI direct comparison

15
MODIS LAI Time Series in Albemarle-Pamlico Basin
16
Understory Removal in 100x100 m plot Effect on
IKONOS NDVI
Before understory cut
After understory cut
Iiames, J. S., Pilant A.N. , Lewis T. Congalton
R. Leaf Area Index (LAI) change detection on
loblolly pine forest stands with complete
understory removal,   Proc. ASPRS 2004 Annual
Conference, 05/23/04, Denver, CO.
17
Understory Removal in 100x100 m plot Effect on
IKONOS NDVI
IKONOS NDVI image
After understory cut
Before understory cut
Understory removal 3 NDVI reduction (plt0.05)
Iiames, J. S., Pilant A.N. , Lewis T. Congalton
R. Leaf Area Index (LAI) change detection on
loblolly pine forest stands with complete
understory removal,   Proc. ASPRS 2004 Annual
Conference, 05/23/04, Denver, CO.
18
MOD15A2 Radiative Transfer vs NDVI Algorithm5x5
km (25 pixels) sample

• Begin your presentation here

19
MODIS NDVI Data Challenges
20
MODIS and Hemiphoto LAI Time Series at
Fairystone Site (deciduous)
21
MODIS and TRAC LAI Time Series at Appomattox Site
(pine)
MODIS LAI spectral profiles from 5 adjacent pixels


LAI 10


Jan Feb Mar Apr May Jun Jul Aug Sep

in situ TRAC LAI
22
LAI Field Data Sets for Archiving
DATA SET DESCRIPTION COMMENTS
HEMI photos Digital hemispherical photographs from survey grids
TRAC sunfleck profiles TRAC profiles from survey transects
Digital ground/canopy photos Digital photos at 0, 45, 90o
Baseline forest biometrics Crown closure, stems/ha, diameter at breast height (DBH), diameter height, canopy analysis, species distribution
Meteorological data NWS, State and cooperative weather observations
23
LAI Image Data Sets for Archiving
DATA SET DESCRIPTION COMMENTS
MODIS LAI Time series Georeferenced period 2000-2005
MODIS NDVI time series Georeferenced period 2000-2005
Landsat ETM images Intermittent 1999-2004 Precision georeferenced
Air photos circa 1990-2002 As apropos
IKONOS data Derived NDVI images As apropos
Digital elevation data 30 m Shuttle Radar Topography Mission Possibly LIDAR for NC
24
Ongoing work

• Validation of TRAC and Hemiphoto methods
• Comparison with destructive harvest at NCSU sites
• TRAC/Hemiphoto repeatability measurements
• Develop 500-1000 m TRAC transect method
• Methods for scaling
• Field Landsat ETMMODIS
• Organize / QA Data Archiving

25

• Begin your presentation here

Thank you!
Acknowledgments NASA State of VA State of
NC NCSU Duke University Westvaco International
Paper
pilant.drew_at_epa.gov