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LINKING IN SITU TIME SERIES FOREST CANOPY LAI AND PHENOLOGY METRICS WITH MODIS AND LANDSAT NDVI AND LAI PRODUCTS
Citation:
Pilant, A, J. Iiames, R S. Lunetta, T E. Lewis, AND J. Ediriwickrema. LINKING IN SITU TIME SERIES FOREST CANOPY LAI AND PHENOLOGY METRICS WITH MODIS AND LANDSAT NDVI AND LAI PRODUCTS. Presented at American Society for Photogrammetry and Remote Sensing Annual Conference and Exhibition, Anchorage, AK, May 5-9, 2003.
Impact/Purpose:
Our research objectives are to: (a) develop new methods using satellite remote sensor data for the rapid characterization of LC condition and change at regional to national scales; (b) evaluate the utility of the new NASA-EOS MODIS (Moderate Resolution Imaging Spectrometer) leaf area index (LAI) measurements for regional scale application with landscape process models (e.g., biogenic emissions and atmospheric deposition); (c) provide remote sensor derived measurement data to advance the development of the next generation of distributed landscape process-based models to provide a predictive modeling capability for important ecosystem processes (e.g., nutrients, sedimentation, pathogens, etc.); and (d) integrate in situ monitoring measurement networks with UAV and satellite based remote sensor data to provide a continuous environmental monitoring capability.
Description:
The subject of this presentation is forest vegetation dynamics as observed by the TERRA spacecraft's Moderate-Resolution Imaging Spectroradiometer (MODIS) and Landsat Thematic Mapper, and complimentary in situ time series measurements of forest canopy metrics related to Leaf Area Index (LAI) and Normalized Difference Vegetation Index (NDVI). NDVI is related to ecosystem state, and LAI is an important input to ecosystem and landscape process models. Current research efforts involve development of remote sensing methodology for detecting landscape change and estimating LAI from satellite, particularly using time series analyses of MODIS data. The U.S. Environmental Protection Agency (EPA) has established a number of long-term forest research sites in the Piedmont and Coastal Plain of the Albemarle-Pamlico Basin of North Carolina and Virginia (USA). At each site, we conduct biophysical surveys of site composition and landscape character, as well as time series optical surveys of LAI at various phenological stages. LAI is estimated indirectly using combined hemispherical photography and
TRAC (Tracing Architecture and Radiation of Canopies) optical surveys arranged in permanent grids and transacts. This research focuses on two fundamental questions: (i) how can LAI be measured accurately and effectively in situ, and (ii ) how can meter-scale field measurements be correlated with kilometer-scale MODIS geophysical products? We present initial results exploring relationships between the in situ LAI time series measurements and MODIS LAI and NDVI image products.