PARENT SESSION
Poster Session #63: Late Breaking and Newsworthy Papers.
Friday, August 9. Presentation from 8:00 AM to 9:30 AM. Exhibit Hall B & C, TCC

Geographic portability of the relationships between LAI, FPAR, and spectral vegetation reflectance .

GIBBS, HOLLY¹, Washington-Allen, Robert^*,1, KING, ANTHONY¹, SALE, MICHAEL¹, ¹ Environmental Sciences Division, OAK RIDGE, TN

ABSTRACT- Accurate spatial prediction of biophysical parameters such as leaf area index (LAI) and the fraction of photosynthetically active radiation absorbed by vegetation (FPAR) is critical for many modeling and monitoring applications. Traditional methods that derive these parameters from satellite data require time-consuming and expensive ground measurements to establish relationships with spectral vegetation indices (SVI) or to calibrate bidirectional reflectance distribution function (BRDF) models. Consequently, correlations and model calibrations established for one site are frequently transferred to another site. We assess this geographic transfer and develop potential corrections as part of a multi-laboratory Department of Energy project investigating hydrometeorological processes in the Walnut River Watershed in southeast Kansas. We apply LAI-SVI correlations and BRDF model parameterizations developed for the North America Great Plains and the Konza Prairie Long Term Ecological Research sites to the Walnut River Watershed. Advanced Very High Resolution Radiometer biweekly Normalized Difference Vegetation Index (NDVI) composites from 1999 and 2000 and NDVI derived from Landsat Thematic Mapper scenes from 1999, 2000, and 2001 were used to evaluate and improve the geographic transfer to the watershed. Preliminary analysis indicates that simple corrections using site-specific satellite data to adjust model parameters (e.g., NDVI of bare ground) improve predictions of the ported LAI-SVI relationships and BRDF model calibrations.

KEY WORDS: FPAR, LAI, NDVI, REMOTE SENSING